Dug Well Design to Safely Access Shallow Groundwater

 The following is from a news release from the U.S. Geological Survey (USGS):

There are three basic styles of modern well construction: Drilled Bedrock Wells or Fractured Rock Wells, Sand and Gravel Wells, Large Diameter Dug and Bored Wells. How you should build a well is determined by type of well (dug or drilled), the local geology (sand, gravel, fractured rock, bed rock, etc.) local precipitation and environmental conditions.

The drilled bedrock or fractured rock wells have become the dominant well in most of the country. Dug and bored wells are generally around three foot in diameter and are less frequently used today because they are very susceptible to contamination.

According to the U.S. Geological Survey (USGS): Dug wells typically have problems with well yield (having enough water for a modern household) and bacteria (contamination). “Traditional dug wells did not produce a lot of water and often ran dry in the summer or in drought, leaving the owner without water. Also, because the older dug wells had many joints in them, bacteria were able to get into the water, and people sometimes got sick. The new drilled wells that went deeper to the bedrock aquifer didn’t have these problems, so people switched (to drilled wells).” 

Joe Ayotte , the Chief of the Environmental Hydrology Section at the USGS New England Water Science Center and  his team have patented a new design for a dug well to solve these problems with supply and contamination. They call their new design a “Novel Dug Well.” The USGS was not trying to revive a quant old well, instead they were trying to solve a newly discovered problem.

Joe Ayotte, the Chief of the Environmental Hydrology Section at the USGS New England Water Science Center has been studying groundwater throughout New England for much of his career. He has found that certain contaminants, like arsenic and uranium, is in the groundwater that many New Englanders use for drinking water purposes. Turns out, the bedrock in much of New England has naturally occurring arsenic and uranium, both of which are elements that are linked to negative health conditions like kidney disease and cancer and negative birth outcomes. I am interested in his work because in many areas Virginia bedrock has naturally occurring uranium and the Virginia Rural Household Water Quality Program has been collecting data looking for arsenic in our groundwater.

Since the problems with the shallow aquifer stemmed from the lack of water in traditional dug wells and the bacteria introduced by the older design, the team from the USGS lead by Mr. Ayotte set out to redesign the dug well to solve these issues.

With colleagues throughout the USGS, Mr. Ayotte came up with  a design for a “Novel Dug Well,” as he called it, that successfully combined a large area of inflow with ample storage to provide sufficient water yield needed by well owners. The well has even proven to be drought resilient. Furthermore, the casing he uses has no joints and is sealed with a sanitary cap to prevent bacteria from gaining access. This enables well owners to access shallow aquifers that avoid the arsenic and uranium problems from the bedrock aquifer.

Once the redesign tested successful, the USGS team received a patent for their new well design. The technology is available for licensing to entities or persons who can manufacture and make use of the research. This could enable well users to reduce exposure to potential deep aquifer contaminants and providing an alternative water supply.

Depending on geology there are other designs available today for shallow wells. More traditional large diameter shallow wells are constructed by machine and are generally of one of two varieties; a bored well with concrete collar or a bored well with a buried slab. In the concrete collar construction the casing is generally 4 or 5 foot sections of precast concrete that are placed on top of each other and allows water to seep into the well through the joints between these sections. Because of the possibility of surface infiltration near the well, the upper 10+ feet around the well is grouted with concrete or has a bentonite seal, but frankly the USGS design seen below appears to be a better option.

from USGS public domain

Figuring Out Why there is No Water from the Well

There are a number of reasons why a well might suddenly stop producing water, but basically they all break down into:

• Equipment failure,
• Piping Leak
• Depletion of the aquifer or other groundwater problems
• Failing well,
• Frozen pipes or well

Equipment problems are the most common so we will start there. The first thing to check for an electrical problem:

• Circuit breaker tripped
• Burned out fuse
• Short, broken or loose wire in the well (may have caused the problem)

If your well stopped working right after a thunder storm, check to see if the well was struck by lightning. This is fairly common in the south and Texas. If there is a short in the pump electrical system it will blow the circuit and if there was a power surge as the pump was turning on a circuit could have blown. To make sure a circuit breaker is not tripped, turn off and on the pump’s circuit breakers or change the fuses. Pumps generally have two circuits tied together because an immersion pump draws a lot of power (240 volts). Make sure both circuits are on- a small water drizzle is one sign of a 240 volt pump getting only 120 volts. If the pump keeps turning off and it is not because of dry well, then there might be a short. A trickle of water or no water could also be frozen pipes. If it’s really cold outside (below zero) check that first.

Intermittent episodes of severe water pressure loss or even no water is usually a sign of a problem with the water supply. If you have water first thing in the morning and again when you get home from work, but the supply seems to run out especially when doing laundry or taking a shower, then the well may be drying out. Diminished flow that is not related to use can be caused by reduced flow through pipes either due to a blockage or cracked pipe. If the water suddenly stops completely that is usually a sign of a mechanical problem.

There is a lot of parts of well system and well design does vary depending on geology, weather, local custom, and age. These days deeper drilled wells are more common, to be less impacted by drought and contamination. The essential components of a modern drilled well system are:

• a submersible pump,
• a check valve or foot valve (and additional valve every 100 feet),
• a pitless adaptor,
• electrical wiring including a control box if the starter is not in the pump itself
• pressure switch
• a pressure tank unless you have a constant pressure pump
• and interior water delivery system.

To keep the home supplied with water each component in the system and well must remain operational. The most common equipment failure to cause sudden loss of water are:

• Failed motor on the pump
• Failed starter for the pump (can either be part of the pump or a separate unit in the basement)
• Defective pressure switch

The components that are usually in the basement are the pressure tank and pressure switch and potentially the starter. These provide consistent water pressure at the fixtures in the house and the electrical switch that turns on the pump. Most water treatment equipment will also be in the basement, but does not usually affect whether or not you have water. The pump moves water to the basement water pressure tank (unless you have a constant pressure pump), inside the tank is usually an air bladder that becomes compressed as water is pumped into the tank. The pressure in the tank moves the water through the house pipes so that the pump does not have to run every time you open a faucet. Reduced water pressure could be due to a water logged or leaking pressure tank.

Read the pressure gauge on your pressure tank. If it is not showing a pressure of 40-60 psi (or 30-50 psi) that could be a sign that the pump is not turning on. The question is why. The pump could have failed, the well could be dry or not have enough water to operate (there is a cut off on the pump to protect it when the water level is low), the pressure switch could have failed. Pressure switch problems are easy to fix. Many models have a manual bypass lever. If yours does you can force the pump on using the lever. If the pressure starts to rise when you press the lever then you need a new pressure switch. The last one I bought was $25.

If the pressure on the gauge was in the desired range, it could be several things. First let’s make sure the pressure gauge is actually working- tap the gauge with the back of a screwdriver (gently) and see if the gauge moves. Both the gauge and pressure switch can clog with sediment. Yes, the gauge on my last pressure switch failed and I did not see it until I was looking for another problem.

If the pump cannot be heard or measured with a voltmeter to turn on when you manually turn on the pressure control switch, then it is either the starter or the motor. The pump is the piece of equipment subject to the most wear and tear and most likely to fail.

There are two types of pumps; a jet pump and a submersible pump. Most modern drilled wells are built with a submersible pump. In shallow wells and dug wells, above ground jet pumps were often used. Dug wells tend to be older and have concrete lids or other large lid. The pump for a dug well is sometimes in a pit next to the well, a well house, or it will be located in the basement. Jet pumps are easier to check since they are not in the well and you can pretty much see if they are running. A jet pump can lose its prime. So if you have a jet pump check that first. You need water to prime the pump. If you do not have a hand pump you can connect to your system and draw water up, run a hose from the hot water heater. If a jet pump continually looses prime, you probably have a leak either in the foot valve, check valve or a line. Look for it.

Most modern well installations are drilled wells with a submersible pump. A drilled well generally has a 6 inch diameter pipe sticking out of the lawn somewhere. A submersible pump can be checked for in the basement with a voltmeter if you cannot hear it operating. The safety switch and control box for the pump should be in the basement on the wall near your pressure switch.

The submersible pump consists of the sealed pump motor connected to a series of impellers separated by a diffuser that drives the water up the pipe (a flexible tube) to the plumbing system through the pitless adaptor and a pipe that runs from the well beneath the ground to the basement. The starter can be either part of the pump or separately housed in the basement. Either the motor or starter can fail. Submersible pumps should last 14-17 years or more, but silt, sand, iron bacteria and excessive mineral content can impact their life. Any impact to the well -hitting the well pipe with a car or lawn tractor, or a bit of gravel broken loose from the formation can damage the pump.

If you can hear or measure that the pump turns on, yet you have no water or only a little the problem might be a failure of the pipe leading from the well to the house. Depending on the distance to the house this can involve quite a bit of excavating to dig up the pipe and replace it. Look for a waterlogged area. Replacing this pipe has to be carefully done and should not be pieced. If the horizontal well piping between well and building does not slope continually upwards or if it has a high spot, an air lock can form in the piping.

If the temperature outside is below zero and you turn on a faucet and either get nothing or just a trickle comes out, suspect a frozen pipe, first. If your well supply line or the water main is not frozen, you may have water in part of the house, but not others. The most likely pipes to freeze are against exterior walls of the home, or are exposed to the cold, like outdoor hose bibs, and water pipes in unheated interior areas like basements and crawl spaces, attics, garages, or kitchen cabinets. Pipes that run against exterior walls that have little or no insulation are also subject to freezing. In sub-zero weather wells with separate well houses can freeze. Keeping the temperature in a well house above freezing will prevent this.

There is no quick way to fix frozen pipes and calling a plumber does not help until the pipes warm up and you can see if any pipes burst. Make sure you know how to turn off the water in case you have a burst pipe (cutting the well power switch will do it). Turn the heat up, open cabinets under the sinks in the frozen bathrooms and kitchens and use ceramic heating cubes if you have them to warm up the area where the pipes are frozen. Plastic piping is considerably more tolerant of freezing than copper pipes. There is a real shot that a plastic pipe can freeze without bursting if all the connections and elbows are sound.

If you need help with a well problem, the Wellcare® Hotline is staffed by the Water Systems Council (WSC), the only non-profit organization solely focused on private wells and small well-based drinking water systems. The Hotline operates Monday through Friday from 8:00 a.m. to 5:30 p.m. Eastern Time, and can be reached at 888-395-1033.

Low Pressure from the Well

A reduction in pressure from the well can have several causes:

1. the well going dry,
2. a leak or blockage in a pipe in or from the well
3. a pump problem
4. a pressure tank or pressure switch problem
5. an electrical problem (pump is running on 120 instead of 240)

Failure of the well itself is rarely sudden; generally there is a slow deterioration. However, during a drought it can seem to happen suddenly when the storage in the well itself is used up in the normal course of the day. If you have water at normal pressure first thing in the morning or when you get home from work, but the pressure seems to fall or the water run out after a little while, then you may have a groundwater supply problem.

While many wells will last decades, over time the amount of water a well yields can decrease. That can be caused by the water table falling due to extended drought, increased use or increased ground cover with roads, driveways, patios and houses in the recharge area. Mineral encrustation and reducing bacteria (often called iron bacteria) buildup can also decrease well recharge by plugging of holes in the well screen, plugging the piping or the filling of openings in the geologic formation itself. According to Penn State Extension the fall in well yield over time can be caused by changes in the water well itself including:

1. Encrustation by mineral deposits
2. Bio-fouling by the growth of microorganisms
3. Physical plugging of groundwater aquifer by sediment
4. Well screen or casing corrosion
5. Pump damage

To provide a reliable supply of water at an adequate pressure for extended use, a drilled well must recharge at a rate greater than the typical domestic demand of 3-5 gallons per minute or have enough storage in the well itself to supply the demand. Each foot of a typical six inch well, has almost a gallon and a half of storage so that a 100 foot of well has 147 gallons. The crudest test of the well itself is to see if you can run it dry. My well is only 150 feet deep, but the static water level has fallen over the years to 43 feet below grade so running the hose (which draw about 3 gallons per minute) should draw down the well in about an hour. I ran the hose for 16 hours back in the spring an never ran it dry. It recharges faster than I was drawing water.

Even on the deepest home wells it would only take 5-6 hours to know if your well is not recharging fast enough and you can run your well dry. If you have more than about 150 gallons available in well storage it is generally enough to supply small household needs till the well can recharge. At that point it is more likely an equipment or system problem. You can potentially repair an encrustation problem (see https://greenrisks.blogspot.com/2020/03/keeping-your-home-supplied-with-water.html)

Equipment problems are the most common well problems. The first step is to check the equipment. The components of a modern drilled well system likely to impact pressure are: a submersible pump, the piping which can develop a leak or become clogged, a pitless adaptor,  the pipe to the house and the interior water delivery system including the pressure tank and pressure switch.

If your water supply has lost pressure, and seems to be drizzling out of your faucet or showerhead at all times, your problem could simply be a loss of pressure in the pressure tank or damage to or a leak in the bladder in the pressure tank. So start in the basement. The components within the basement provide consistent water pressure at the fixtures in the house and the electrical switch that turns on the pump. The pump moves water to the basement water pressure tank, inside the tank is an air bladder that becomes compressed as water is pumped into the tank. (There are other types of pressure tanks that do not have a bladder and a constant pressure pump does not need a pressure tank, but those installations are not as common.)

The pressure in the tank moves the water through the house pipes so that the pump does not have to run every time you open a faucet. The pressure tank typically maintains the water pressure between 40-60 psi or 30-50 psi for smaller tanks. After the pressure drops below the cut in pressure (typically 30-40 psi), the electrical switch turns on the pump and the pressure in the tank increases as the tank fills. If however, the pump is not delivering water fast enough the pressure tank could fail to regain its head while the water is in use. The pressure switch could also be the problem; it could be cutting in at the wrong pressure.

The first two things to check are the pressure in the pressure tank and your circuit breakers to make sure that the problem is not electrical. You can check the pressure on most pressure tanks with a tire gauge and the valve on the top. (Be sure to cut the power to the system and open a faucet to drain the tank before you measure the pressure. While the water is running out of the tank check the pressure on the pressure gauge, to make sure it is dropping and the pressure gauge is working). After thatyou’re your tier gauge to checking to see that the pressure in the tank is a couple of psi below the cut-in pressure set on your pressure switch. (Most are set to 38 psi for the 40-60 psi tanks.) When you unscrew the cover over the valve if water leaks out, your pressure tank bladder has failed, and it’s time to buy a new one.

The electrical switch in front of the the pressure tank (grey box under the gauge) turns on the pump. It is probably working since you have water, but check it anyway. Check the voltage before and after the switch just to make sure. When the pressure in the pressure tank falls to 40 psi (30 for small tanks) the switch at the pressure tank turns on the pump. Also, you can get what is essentially a vapor lock and the tank may simply need to be drained, bleed and recharged. Before you do that check to make sure that the tubing to the valve is not clogged.

When you turn the pump back on make sure that both circuit breakers are flipped to the on position. If there is a short in the pump system it can blow a single circuit. The pump can operate this way, but not very well. So turn off and on the pump’s circuit breakers or change the fuses. Pumps generally have two circuits tied together because an immersion pump draws a lot of power (240 volts). Make sure both circuits are on- a small water drizzle is one sign of a 240 volt pump getting only 120 volts. (If you know how to do it check the amperage across the pump to make sure it is steady and within range see the chart below from Franklin Electric.) In most cases the pump operates near the maximum load.

Time to look for problems outside. The pipe to the house or the pitless adaptor might have cracked. If like me your pipe runs under a portion of the driveway, this turns out to be a fairly expensive, but simple fix-excavating the pipe and replacing it. Look for signs that a pipe outside of the well is leaking, sinking ground, cracks in the driveway vegetation that looks a little too lush. If you end up replacing the pipe, make sure you slope it properly. If the horizontal well piping between well and building does not slope continually upwards or if it has a high spot, an air lock can form in the piping, so make sure if you end up replacing the pipe that it is properly slanted and not just a fixed depth below surface. The piping in the well itself can also develop leaks over time that can diminish flow.

If you do not see a leak from a pipe outside the well, you are going to have to look at the pump and equipment in the well. At this point, you are going to need help to identify the problem. It is more than a one man (or woman) job to pull a pump. Shallower pumps can be pulled by hand if you are a big, strong and young guy, but special equipment is necessary to pull a deeper pump even for a big guy in great shape. Call a well driller or a well repair company. The well drilling companies can generally replace, pumps and pressure tanks and other well components. In addition, they can diagnose an improper well design. Private well construction was not regulated in Virginia until the 1992 (though Prince William County had well regulations going back to 1979). I have seen some very odd well designs over the years. In Virginia a license is necessary to work on a well as a certified water well provider. Plumbers generally do not have this certification. Do not call a plumber for a well problem.

There are two types of pumps; a jet pump and a submersible pump. Most modern drilled wells are built with a submersible pumps. In older pump installations and dug wells, above ground jet pumps were often used, which can loose it prime. Both types of pump have a fitting called a foot valve. A foot valve is also used at the base of deep wells and is basically a check valve combined with an inlet strainer (older immersion pumps sometimes have what looks like a sock protecting the inlet). Both of these serve as a strainer to prevent picking up rocks or debris that could clog or jam the foot valve. They can get clogged and diminish flow.

Another possible problem is a leak or clog in the pitless adaptor. That is the fitting that allows the vertical well to connect to the horizontal pipe to the house below the frost line. Things like a leaky valve at the bottom of the well can result in a pump losing it prime after a power failure. The submersible pump is a long cylindrical unit that fits within the 6 inch diameter well casing. The bottom portion consists of the sealed pump motor connected to a series of impellers separated by a diffuser that drives the water up the pipe (which is black tubing in the picture) to the plumbing system through the pitless adaptor and a pipe that runs from the well beneath the ground to the basement.The piping or tubing within the well can fail or get clogged.

Finally your pump might be failing. According to the Water Systems Council a submersible pump should last 15 years or more, but silt, sand, iron bacteria and excessive mineral content can impact their life. A submersible pump operating high sediment water may fail in only a few years and a failing pump may appear as diminished pressure before complete failure.

If you need help with a well problem, the Wellcare® Hotline is staffed by the Water Systems Council (WSC), the only non-profit organization solely focused on private wells and small well-based drinking water systems. The Hotline operates Monday through Friday from 8:00 a.m. to 5:30 p.m. Eastern Time, and can be reached at 888-395-1033. Also, if you are in Virginia you can call or email the Virginia Master Well Owner’s Network for help.

Signs that a Well is Going Dry

The most common reason a well stops producing water is a mechanical problem like pump failure, pressure switch failure, loss of power or other mechanical problem. Failure of the well itself is rarely sudden, but rather happens slowly over time. If your water supply has lost pressure, and seems to be drizzling out of your faucet your problem could simply be a loss of pressure in the pressure tank from damage to or a leak in the bladder or simply a failed pressure switch. If your water pulses as it comes out of the faucet, the most likely cause is short cycling of the pump, which could be caused by inadequate water supply as the well goes dry or another faulty component in the system like the pressure switch. However, there are times that the problem is the well and the water supply. The major signs that a well is going dry are:

1. Water pulsing or sputtering out of the faucet. 
2. The water is muddy and filled with sediment and sand. 
3. Loss of water pressure after doing laundry and bathing, but restored water overnight 

As mentioned above, these can also be signs of other problems, so actually measuring the water level and recharge rate in your well should be done before you spend money replacing equipment or thinking of drilling a new well. In a well, a diminished water supply can be caused by drop in water level in the well due to drought or over pumping of the aquifer, or the well could be failing in several other ways.

The water level in a groundwater well usually fluctuates naturally during the year. Groundwater levels tend to be highest in the early spring. Groundwater levels begin to fall in May and typically continue to decline during summer. Natural groundwater levels usually reach their lowest point in late September or October when fall rains begin to recharge the groundwater again. The natural fluctuations of groundwater levels are most pronounced in shallow wells that are most susceptible to drought. Older wells tend to be shallower.

However, deeper wells can also be impacted by an extended drought. Land use changes that increase impervious cover and stormwater velocity preventing recharge from occurring over a wide area and can make existing wells more susceptible to drought. Significant increases in groundwater use can overtax and aquifer.

Unless there is an earthquake or other geological event groundwater changes are not abrupt and problems with water supply tend to happen slowly over time. If your well tends to dry out during the summer when you try to do a load of laundry, you might want to address the problem before there is a drought when your well is likely to go dry. Addressing the problem could be as simple as implementing water conservation measures, or could require replacing water fixtures, lowering a pump or deepening or replacing the well.

In a well, a diminished water supply in a failing well is characterized by a short period of adequate water in the morning (or after resting the well for hours or days) and then almost a complete loss of water. Most modern pumps will automatically shut off when the well runs out of water. This is why a dry well is often mistaken for a failed pump.

Another symptom of a drying out well is loss of water after doing a load or two of laundry. (A top loading washing machine uses about 51 gallons of water and a front loader uses 27 gallons.) What is happening is overnight the well bore hole is filling with as much water as it can still produce and when there is water in the bore hole the pump will turn on in response to the pressure switch and the pressure tank gets filled. Even a tenth of a gallon a minute will still be able to fill the pressure tank overnight and give you enough water for a bit of a wash up in the morning (depending on whether you have low flow toilets, sinks and showers).

• This low flow to the well can be caused by many things some which are fixable, some which are not: 
• A drop in water level in the well due to drought or over pumping of the aquifer. 
• The fractures that feed water to the well could be failing due to a buildup of dirt, sediment and gravel reducing the flow to the well. 
• There are times that the steel casing that lines the first 40-60 feet of a well does not extend deep enough and the well walls crumble over time filling the well with dirt and gravel. 
• Geological events can cause a sudden failure of a well. 

One or more of these factors could be the cause of a well problem. If your water loss seems to be from failure of the well itself, the first step is to call a well driller and measure the water level and recharge rate of the well. That information will tell you what you are dealing with and what choices you have to fix the problem. For the next steps

Coliform “PRESENT”- How to Fix it

This spring in the well water clinic we run each year we found 25 wells out of 114 that had coliform "PRESENT." On a state level, the occurrence of coliform is higher. Of the approximately 7,000 households that participated in the Virginia Household Water Quality Program clinics from 2007 to 2015  they found that 41% of the wells had coliform bacteria, and 9% had E. coli bacteria. Though the 7,000 households may not be representative of all private drinking water wells in Virginia, it is the largest database on private drinking water wells available. It is safe to say that coliform contamination is widespread. 

If your water is contaminated with coliform but not fecal coliform or E. coli, don't panic. You have a nuisance bacteria problem and the source may be infiltration from the surface from rain or snow melt. Typical causes are improperly sealed well cap, well repairs performed without disinfecting the well, failed grouting or surface drainage to the well. If your well had coliform bacteria present you should shock chlorinate the well, repack the soil around the well pipe to flow away from the well and replace the well cap. Then after at least two weeks and the next big rainstorm retest the well for coliform. If coliform bacteria is still present then a long-term treatment should be implemented: using UV light, ozonation, or chlorine for continuous disinfection. These systems can cost up to $2,000 installed.

If your well test PRESENT for coliform standard protocol is:

1. Carefully check the well and water system for points of contamination. Make sure you have a sound and secured sanitary well cap and that the soil around the well is packed to drain water away from the well. 
2. Then treat the well and plumbing system with chlorine for 12-24 hours to disinfect system (the 12-24 hours is essential). Then flush the chlorine from the system- not to your septic system. Make sure that this is done correctly. 
3. Retest the water after the chlorine has left the system in about 10 days to two weeks. If coliform bacteria is “ABSENT” you’re done. If not, then it is time to install a long term disinfection system. (UV light or continuous chlorination)
   
   

In an existing well system that formerly was bacteria free look for these defects:

• A missing or defective well cap and check seals around wires, pipes, and where the cap meets the casing may be cracked, letting in contaminants. 
• Contaminant seepage through the well casing - cracks or holes in the well casing allow water that has not been filtered through the soil to enter the well. This seepage is common in the wells made of concrete, clay tile, or brick. This can also happen to a steel pipe well that was hit by a piece of equipment such as a car, snow blower, lawn tractor or mower or that has rusted. 
• Contaminant seeping along the outside of the well casing - many older wells were not sealed with grout when they were constructed or the grouting has failed. Check the grouting carefully especially if water seems different after severe rains. 
• Well flooding - a common problem for wellheads located below the ground in frost pits that frequently flood during wet weather. 

Coliform bacteria are commonly found in soil, on vegetation, and in surface water. Some coliform bacteria strains can survive in soil and water for long periods of time. Coliform bacteria will not likely cause illness. Coliform bacteria do not occur naturally in most aquifers. Fractured or creviced bedrock aquifers that are close to the surface are the exception. Be aware that there are three different groups of coliform bacteria; total coliform, fecal coliform and Escherichia coli (E. coli) each has a different level of risk. If your water is contaminated with coliform but not fecal coliform or E. coli, then you have a nuisance bacteria problem.

Bacteria washed into the ground by rainfall or snowmelt are usually filtered out as water seeps through the soil, so properly constructed water wells do not typically harbor Coliform bacteria. However, coliform bacteria can persist within slime formed by naturally occurring ground water microorganisms. The slime (or biofilm) clings to the well screen, casing, drop pipe, and pump and may even invade filter systems. Disturbances during pumping or well maintenance can cause the slime to dislodge, releasing the coliform bacteria.

Keep in mind that coliform bacteria do not always show up in every sample. They can be sporadic and sometimes seasonal when they occur in a water supply. You should not continue drinking water contaminated with coliform, either boil the water drink bottled water until you disinfect your well. Bring the water to a rolling boil for one to five minutes (the higher the elevation the more time is necessary) to kill the bacteria. You may also want to consider using bottled water as a temporary drinking and cooking water source.

You may have received a total coliform count. This gives you a general indication of the sanitary condition of a water supply and extent of the problem. Bacteria can be introduced into a new well during construction and can remain if the water system is not thoroughly disinfected and flushed. Well construction defects such as insufficient well casing depth, improper sealing of the space between the well casing and the borehole, corroded or cracked well casings, and poor well seals or caps can allow surface water or insects to carry coliform bacteria into the well. These problems are common and the most likely source of the coliform bacteria contamination. Unplugged abandoned wells can also carry coliform bacteria into deeper aquifers.

Since bacterial contamination cannot be detected by taste, smell, or sight, all drinking water wells should be tested at least annually for Coliform bacteria.

a sanitary well cap

typical drilled well

Is My Groundwater Being Used Up?

I breathed a big sigh of relief when the rains came last week. I live in the northwest corner of Prince William county that is often shielded from rain; it can be pouring 5 miles down the road in Haymarket and dry here. Earlier this month the groundwater level in the U.S. Geological Survey (USGS) monitoring well up the road from my home recorded its lowest level in 86 years and I began to worry about my water supply. Now, water levels have crawled back up to the 10th percentile and I am watchful but not worried.

Groundwater is water beneath the surface of the earth. It is one of our Nation's most important natural resources and is often taken for granted. According to the U.S. Geological Survey (USGS) groundwater is the provides 38% of public water supplies in our country. In addition, groundwater is the sole source of drinking water for more than 97% of the rural population who are not connected to city or community water systems. I am one of the 46 million Americans who depend on a private well for their water, so I care very much about groundwater, its sustainability and its protection.

My well draws on an unconfined aquifer. A water-table, or unconfined, aquifer is an aquifer whose upper water surface (water table) is at atmospheric pressure, and thus is able to rise and fall with moisture that is contained in the earth. Water-table aquifers are usually shallower than confined aquifers are. Because they are shallow, they are impacted by drought conditions much sooner than confined aquifers. A confined aquifer is an aquifer below the land surface that is saturated with water. Layers of impermeable material are both above and below the aquifer, causing it to be under pressure so that when the aquifer is penetrated by a well, the water will rise above the top of the aquifer.

The water level in the aquifer that supplies a well does not always stay the same. Droughts, seasonal variations in rainfall, and pumping affect the level of the water table. If a well is pumped at a faster rate than the aquifer around it is recharged by precipitation or other underground flow, then water levels in the well can fall. This is what happens during times of drought and happened this summer when there was little or no rain in our little micro-climate. A well is said to have gone dry when the water level falls below the pump intake. This does not mean your well will never have water in it again, as the water level may come back through time as recharge increases. If drought has caused the water level to fall, then precipitation can restore the well.

There are other forces that can impact the recharge of a well. Land use changes that significantly increase impervious cover and stormwater velocity can prevent water from soaking into the earth and reduce recharge of the groundwater making existing wells more susceptible to drought. Significant increases in groundwater use for irrigation of crops or playing fields, or commercial or industrial purposes can overtax and aquifer and dry out neighboring wells. Unless there is an earthquake or other geological event groundwater changes are not abrupt and problems with water supply tend to happen slowly as demand increases with construction and recharge is impacted by adding paved roads, driveways, houses and other impervious surfaces.

The water level in a groundwater wells naturally fluctuates during the year. Groundwater levels tend to be highest in the early spring after winter snowmelt and spring rainfall when the groundwater is recharged. Groundwater levels begin to fall in May and typically continue to decline during summer as plants and trees use the available shallow groundwater to grow and streamflow draws water. Natural groundwater levels usually reach their lowest point in late September or October when fall rains begin to recharge the groundwater again. It is concerning that the monitoring well recorded its lowest level in 86 years.

The natural fluctuations of groundwater levels are most pronounced in shallow wells that are most susceptible to drought. Older wells tend to be shallower. However, deeper wells may be impacted by an extended drought and take longer to recover. My well is fairly shallow in a fractured rock system with little overburden. During dry periods, I can watch the water level fall. The chart below is from a nearby USGS monitoring well.

Private wells draw their water from groundwater. Geology, climate, weather, land use and many other factors determine the quality of the groundwater; and the water level in your well depends on a number of things, such as the depth of the well, the type (confined or unconfined) of aquifer the well taps, the amount of pumping that occurs in this aquifer, and the amount of recharge occurring. Within Prince William County Virginia there are four distinct geologic provinces: (1) the Blue Ridge, (2) the Culpeper Basin, (3) the Piedmont, and (4) the Coastal Plain. The northwestern part of Prince William County down the hill from Bull Run Mountain, consists of sedimentary rocks of the Culpeper Basin. The predominant rock types are conglomerates, sandstones, siltstones, shales, and argillaceous limestones. This geology tends to have moderate to excellent water-bearing potential because it is a fractured rock system with very little overburden. The highest reported yields in the county are from wells in this geology.

It is concerning that the seasonal lows are getting lower. This is a sign that the present groundwater use is not sustainable. Since we do not know what the total available water is, it is impossible to know how critical the overuse or diminished recharge of the aquifer is. According to studies by a group of researchers at the University of California, Irvine, the University of Texas, and the Hydrological Sciences Branch at NASA GSFC using satellites to perform real world groundwater monitoring Virginia’s aquifers are under stress. That means that we are using up the groundwater faster than it is recharging. That is exactly what an 86 year low level of groundwater is telling us.

Well Water Problems- The Hot Water Smells and is Oily

Regularly, I receive questions about people’s wells through my blog. Recently I received the following question:

Our well water great then all of a sudden for the past month we get this smell from our water (only the hot water) and it leave an oily texture on our skin and also has this foul smell. We tried cleaning the hot water tank and that did nothing. Don't know what else to do!

Often there are limits to how helpful I can be to questioners because there is not enough information, but this sounds like hydrogen reducing bacteria have taken up residence in the hot water heater. There is an easy fix for this.

First a little background. Hydrogen Sulfide gas (H2S) with its characteristic “rotten egg” taste and smell can actually be detected as an off smell at 0.5 parts per million (ppm) by most people. At less than 1 ppm, hydrogen sulfide will give water a musty odor. At 1 to 2 ppm, it will have an odor similar to rotten eggs. Levels encountered in private wells are usually less than 10 ppm, because high levels of gas will not remain in solution in the water. Though toxic at 800 parts per million, Hydrogen sulfide is heavier than air and can accumulate in pits and basements and can potentially create a health and explosive hazard (though the smell might kill you first).

Hydrogen sulfide can end up in your tap water by four different routes. (1) It can occur naturally in groundwater especially in oil rich shale and coal seams. (2) It can be produced within the well or plumbing systems by sulfur reducing bacteria (bacteria that essentially eat sulfate in areas that have a high natural level of sulfate in the rocks. These anaerobic bacteria occur naturally in decaying plant material and soil and many areas in the nation have high natural levels of sulfate in the groundwater. (3) Hydrogen sulfide can form in hot water heater by either supplying a pleasant environment for the sulfate reducing bacteria to thrive or the energy for the magnesium rod intended to prevent corrosion of the heating tank to react with the sulfate naturally occurring in the water. (4) Finally, there are instances where the hydrogen sulfide gas is due to contamination of the well with septic waste.

Back to the problem at hand. Because hydrogen sulfate is so easily smelled by the typical human being, smell alone is enough to identify the problem. Also the description of the water as feeling oily is enough to identify the sulfur reducing bacteria. These are the classic symptoms of sulfur reducing bacteria creating hydrogen sulfate in the hot water heater. Though, I would have describe the feel of the water as slimy (after all I know what’s in it), the questioner’s description is classic for this problem.

If the smell is only from the hot water faucet and not from the cold water, then the problem is in the hot water heater. It is either sulfate reacting with the magnesium anode rod, or sulfur reducing bacteria (flourishing) in the hot water tank. The description of the water as oily would indicate the problem is sulfur reducing bacteria flourishing in the hot water heater. The reason that cleaning the hot water tank did not work is that the reducing bacteria were probably originating in the well and the water has naturally high levels of sulfur.

There is no standard test for sulfur reducing bacteria, so without the feel of oil it is often difficult to differentiate between a bacteria problem and something that might be solely sulfate reacting with the magnesium rod in the tank beyond the feel of the water. Also, hard water and certain soaps can leave a residue easily confused with the feel of reducing bacteria in the water. Thus, it is generally best to treat the hot water tank for both sulfate reducing bacteria and for the magnesium rod reacting with the sulfate naturally occurring in the water. It is a good idea to chlorine shock the hot water heater to kill the bacteria then flush it. But first start by raising the temperature in the hot water heater to 160 degrees Fahrenheit for three hours or more. This will generally kill the sulfur reducing bacteria. Hot water tanks use a lot of energy to keep the water hot, and we have all been advised to lower the temperature on the tank to 140 degrees Fahrenheit to save energy. Unfortunately, that is a temperature at which reducing bacteria thrive. So, pump the heat all the way up and kill the bacteria.

At this point you might want to flush the hot water heater a couple of times and let it heat back up and see if the problem is gone. Even if this works, the cure probably won’t last. It is likely that the iron bacteria are being introduced from the well, but keeping your hot water heater at 160 degrees will constantly kill the bacteria. If you do not want to keep your hot water heater set so high, then move on to disinfecting the hot water heater and replacing the anode rod and know that you will have to regularly disinfect the hot water tank. I dealt with a similar problem by disinfecting the hot water tank then simply keeping the hot water very hot. I bought an insulated cover for the tank to cut down on the power usage.

It is not very hard to disinfect a hot water tank, but unless you are very familiar with operations and maintenance of hot water heaters, you should call a plumber. Either turn off the hot water heater if it is electric or put it on pilot if it is gas and drain off a few gallons of water after you close the cold-water inlet valve. Make sure that you have drained off at least a few gallons and pour a half gallon of household bleach (5.25% hypochlorite) mixed with water into the tank. The best way to get the bleach into the tank is to use a funnel and either the temperature and pressure valve opening, anode rod opening, or hot water outlet pipe opening to pour the chlorine into the hot water heater. Let the chlorine sit in the tank for at least two hours. Then open the cold-water inlet valve, drain the hot water heater and turn the heat back up. If the problem is sulfate reacting with the magnesium anode (corrosion protection rod), it can be replaced with an aluminum rod that is not as reactive as the magnesium and may still serve to protect the metal components of the tank from corrosion. Most hot water tanks take a standard size anode rod and there are aluminum replacements available from several manufacturers. Generally, you should check the condition of the anode rod when you pour the bleach into the tank. Be aware that some high end tanks have two anode rods and replacing just one with aluminum will not solve the problem because the remaining magnesium rod will continue to react with the sulfate.

For instructions on how to identify the source of your hydrogen sulfate problem and solve it see Hydrogen Sulfide-the Rotten Egg Smell in Well Water.

Plan Now to Replace Your Well Pump

If you have a private drinking water well you are responsible for maintaining your well and water system to keep the water flowing to your home. There has been limited data gathered on private household water wells over the years, so a lot of what’s out there is hearsay and guesswork. The Virginian Rural Household Water Quality Program out of Virginia Tech through its well testing program is gathering data, but for now the data available is limited.

Both wells and the mechanical components of a well have a limited life. Someday the well components and well its self will have to be replaced- plan and budget for it now because you cannot live without a water supply. To avoid costly mistakes, the time to research well contractors and equipment is before your well fails. While many wells will last decades, it is reported by the groundwater association that 20 years is the average age of well failure that is failure of the well itself. Failure of the well components were not tracked separately. Mechanical failure is impacted by the type of well, the geological conditions, how it is operated and maintained and the materials of construction. In other words, it varies all over the place.

A well may fail through pumping water high in sand or gravel, corrosion from corrosive water (low pH), incrustation of the well by minerals, biofouling of the well by microbial oxidation and precipitation of iron, manganese or sulfur and the slime production, or by a failure or breakdown in the pumping equipment. Often these problems are interrelated and we will discuss that in a later blog entry. Water treatment systems are installed to protect plumbing and improve water quality in the house. Nothing is done to protect the well or keep it operational.

The essential components of a modern drilled well system are: a submersible pump, a check valve (with an additional valve every 100 feet), a pitless adaptor to bring the water to the house below the frost line, a sanitary sealed well cap to keep out vermin and bugs, electrical wiring including a control box, pressure switch, a pressure tank to literally push the water throughout the house and an interior water delivery system known as your plumbing. There are additional fittings and cut-off switches for system protection, but the above are the basics. To keep the home supplied with water each mechanical component in the system and well must remain operational and sooner or later they should all be replaced.

The well has a casing (a metal or plastic liner) that may extend the length of the well, or at least to the bedrock and then have some sort of slotted casing, screen or “sock” around the pump impeller to keep debris, sand and sediment out of the system. Over time these can become damaged by corrosive water, fouled by “iron bacteria” or clogged by sand or clay fines all of which can destroy your well’s mechanical equipment.

When you drill a well, mud and borehole cuttings can partially plug the well. This material must be removed to allow water to freely enter the well during well development. A good well driller will do a better job of this, a less than good well driller will tell you that excess sediment in your new well needs a sediment filter and will happily sell you a new pump when the first one fails prematurely from pumping sand and grit. All wells have sediment, but if the well has not been fully and properly developed the well will often produce excess amounts of sediment or have a low water production yield. Though not every well drilled has the potential to provide enough water for a household, poor choices in well completion design can render even a good well a poor producing well and result in a very short life for the mechanical equipment.

Well casings are subject to corrosion, pitting and perforation. Also, over time the amount of water a well yields can decrease. That can be caused by the water table falling due to extended drought, increased use or building in the recharge area or a deterioration in the equipment efficiency. Mineral encrustation and biofouling can cause plugging of holes in the well casing, well screen or the filling of openings in the geologic formation itself that supply water to the well. The most common encrustation and plugging of a well or its components is from the conversion of calcium bicarbonate which is soluble in water to calcium carbonate which is insoluble and caused by the reduction in pressure by the pumping action.

If you rely on a private well for your water supply, like me and 1.7 million other Virginians, you are completely responsible for routine testing, care and maintenance of that system and you should think about your water supply and equipment and plan for replacement before you have a problem. Some health departments in parts of the country that iron rich recommend chlorinating your well once a year and anytime it has been opened or serviced as a method to prevent biofouling. I chlorinate my well every couple years to address “iron bacteria” that has been a problem in the past. This also serves to keep my well fresh. When I chlorine shock the well I am essentially flushing the water system to remove residue and buildup from the system.

Somewhere in the back of my head is the statistic that the median run time for an immersion pump is about 25,000 hours that gives you about 14-17 years of residential operation depending on how your household operates. My well pump is about 12 years old, while it is my intention to replace my pump, the wiring, the pressure tank and pressure switch before they fail, it is devilishly hard to pick a time to do that. However, I can be prepared to replace the pump and related components by researching that option now. After you pump has failed is not the time to identify a contractor and pick the replacement equipment. Identifying who to call if you have a well problem is something all well owners should do before they have a problem.

The first step is to get a list well contractors where you lie who are licensed to operate in in your state. In Virginia, there have been well regulations in place since 1992 and well contractors are required to have a license from the Department of Professional and Occupational Regulation (DPOR) as a water well system provider. Loudoun County Health Department is kind enough to maintain a public list of licensed well contractors which you can access from their web site.

You should get three proposals to compare, so you will need to narrow the list of contractors based on reputation, size of the organization and references. Call the licensed contractors and ask about availability-when your well fails you do not want to wait a week or more for an appointment. Next get at least three references for pump and pressure tank replacements from each and call them. Get as much information as you can from the references and do not forget to ask if they would use the well contractor again. Also, make sure that the well contractor has the proper equipment to pull your existing pump vertically.

Once you have selected your well contractors you need to call them for a proposal which should include equipment specifications, labor and costs. It might be a good idea to replace the pump, pressure tank and electrical at the same time, I am a big believer in this, but you should discuss this with your selected contractors. Do you want to install a 2-wire or 3-wire model pump? A 3-wire model makes maintenance easier. This is because the starter controls are above ground, wired to the pump. What size pump do you need 1 HP or 1.5, 2.0 or maybe 3.0 HP? How many gallons a minute should it pump? Do you need or want a variable speed pump? Variable speed pumps have been reported in some places to have reliability problems. What size pressure tank do you need? Are you going to replace the electrical wiring? These are all questions you want the well contractor to answer and options you want to price out while you still have water in your house. Your well contractors will not all have the same answers, you will then need to decide what you want. By going through this exercise you will be prepared to deal with both mechanical and well issues when they happen.

The Causes of Reduced Well Flow

If your household water is supplied by a well, responsibility for maintaining your water supply falls to you, and there are many potential causes of what seems to be a loss of water pressure or water volume. In a well, a diminished water supply or well yield can be caused by drop in water level due to drought or over pumping of the aquifer, the well could be failing or fouling or there might be an underlying well construction or design problem. There are also equipment problems that seem to mimic a failing well- a leak in the pitless adaptor or pipe to the house or a worn or damaged pump impeller could reduce well flow or water pressure. Remember that equipment problems are the most common cause of well problems. So let’s start there.

The essential components of a modern drilled well system are: a submersible pump, a check valve (with an additional valve every 100 feet), a pitless adaptor to bring the water to the house below the frost line, a sanitary sealed well cap to keep out vermin and bugs, electrical wiring including a control box, pressure switch, a pressure tank to literally push the water throughout the house and an interior water delivery system known as your plumbing. There are additional fittings and cut-off switches for system protection, but the above are the basics. To keep the home supplied with water each mechanical component in the system and well must remain operational.

A leak in the piping from the well to the house could reduce the well flow, a damaged pump or the components in the basement that provide consistent water pressure and the electrical switch that turns on the pump. Look for indication of moisture, and subsidence to find a leaking pipe between the well and the house. In the house water goes into the pressure tank. Inside the pressure tank is an air bladder that becomes compressed as water is pumped into the tank. The pressure in the tank moves the water through the house pipes so that the pump does not have to run every time you open a faucet. The pressure tank typically maintains the water pressure between 40-60 psi or 30-50 psi for smaller tanks. After the pressure drops below the cut in pressure (typically 40 psi), the electrical switch turns on the pump and the pressure in the tank increases as the tank fills. If however, the pump is not delivering water fast enough the pressure tank could fail to regain its head while the water is in use. Also, jiggle the tank to make sure that there is not a hole in the bladder and the area above the bladder is not filling with water and becoming water logged. Sometime just draining the pressure tank, bleeding the air out and recharging it will improve a situation, but like any mechanical piece of equipment pressure tanks do wear out.

from USGS

The well itself can also be the cause of reduced well flow. The well has a casing (a metal or plastic liner) that may extend the length of the well, or at least to the bedrock and then have some sort of slotted casing, screen or “sock” around the pump impeller to keep debris, sand and sediment out of the system. In Virginia, there have been well regulations in place since 1992 to prevent poorly designed and developed wells but, it still happens and there are still a huge number of wells that predate regulations.

If you are having a well drilled check to make sure that the well driller is licensed and that the well is built according to regulations (if your location does not have well construction regulations check the regulations in other states or provinces to make sure you get a quality well). Always use a local well driller with experience in your immediate vicinity, the type of well construction must be matched with the geology and the characteristics of the aquifer. Experience is often helpful (but not everyone is capable of understanding and learning from experience). An understanding of geology and hydrology, very local and detailed regulation, or enough experience of knowing what has worked before is essential when choosing between a perforated well casing or well screen, identifying the right size slotting or screening to use, the placement within the borehole of the screening or perforated liner, whether a sand pack is necessary and where to locate the pump in the well. Poor choices in any of these items could cause problems with excess sediment in your water or reduced well yield.

When you drill a well, mud and bore hole cuttings can partially plug the well. This material must be removed to allow water to freely enter the well during well development. A good well driller will do a better job of this, a less than good well driller will tell you that excess sediment in your new well needs a sediment filter and will happily sell you a new pump when the first one fails prematurely. Sediment does tend to reduce in the first year because not all of the cuttings are removed during well development. If the well has not been fully and properly developed, the well will often produce excess amounts of sediment or have a low water production yield. Though not every well drilled has the potential to provide enough water for a household (even in my water rich part of Virginia), poor choices in well completion design can render even a good well a poor producing well.

Groundwater supply can change because groundwater systems are dynamic. In the Valley and Ridge of Virginia (west of 95 and before the Appalachian Plateau) the geology is characterized by unconsolidated overlay underlain by fractured rock. In the Piedmont region the fractured rock tends to be sedimentary rock and is carbonate rocks within the areas of karst terrain. Fractured rock systems tend to be water rich areas of Virginia, but not uniformly so. In the fractured rock systems of the Valley and Ridge wells draw groundwater from fractures in the bedding plane which run parallel to the vertical fractures. Fractures can run dry or become encrusted. In unconsolidated sediments of the coastal plain ground water is pulled from the saturated zone, but the wells needs to be screened. In the Appalachian Plateau which is a flat layered rock system with horizontal fractures, the coal seams are typically the aquifer and groundwater is typically shallow. Coal country is the location of many shallower dug wells which easily go dry during times of drought.

While many well problems are caused by poor construction, development or operation of the well, the geology can also be a source of problems. Reduced well yield can be caused by lack of recharge. The water withdrawn from an aquifer can be increased by building homes and increased use for irrigation, domestic watering of gardens and/or reduced recharge. The more land area that becomes covered with pavement, and buildings the less water percolates into the ground and recharges the aquifer. If water is withdrawn from a well faster than the aquifer is able to produce, the well is over-pumped and that is reported to be the most common cause of premature well failure. Over-pumping not only depletes the groundwater, but it rapidly increases the rate of sediment drawn into the well by the pumps suction, causing plugging of the perforated area where water flows into the well. It can also cause corrosion, incrustation and biofouling or the aquifer to compact which further restricts water flow to the well.

Sometimes a decline in water level is seasonal or due to a drought. Typically water levels are higher in spring and lower in the fall. Extended dry periods can also impact water levels, especially in shallow aquifers supplying dug wells. Checking the water level in your well or a nearby proxy monitoring well is a way to identify water level trends and aquifer depletion before the problem becomes serious. If you have the opportunity to install a level monitor for your own well, it is a way to identify a failing well or diagnose a problem, but in most instances it is not practical. For years I have coveted a water level monitor (also a Viking stove- but I don’t have either).

Mineral incrustation is a common problem in some aquifers where there is an abundance of dissolved minerals including calcium, magnesium and iron, as well as iron bacteria. If you have hard water, you well can become encrusted when minerals precipitate or settle out during the pressure changes in the pumping process. This causes scale deposits on the casing, liner and screens. Over time incrustation can reduce the flow of a well. If you have scale formation within the well a well can be treated with chemicals or acid or in some geology gently hydraulically fractured. To do this “right” takes equipment and knowledge. There are well treatment specialists and lots of people who have no clue. Be award that an old metal casing may not survive chemical or mechanical treatment and the well may collapse.

Installing and pumping a well often introduces bacteria into the subsurface and increases the level of oxygen and nutrients in the well and surrounding aquifer. Naturally occurring bacteria, such as iron bacteria or sulfur reducing bacteria, may thrive under these conditions. Iron bacteria, sulfur reducing bacteria and related bacteria can form a gel-like slime that captures chemicals, minerals and other particles such as sand, clays and silts. "Biofouling" occurs when the accumulations of gunk are sufficient to reduce water flow through screens and slats or impair the pump. This can mean reduced well yield and water quality. Iron bacteria buildup is a problem that I have dealt with. A couple of years ago I chlorinated the heck out of the well (800 ppm chlorine- I kid you not). That single treatment has kept my house and hopefully my well iron bacteria free since. I keep an eye out for slime build-up on the toilet flappers and will treat the system again when necessary- before I have reduced well yield or pump damage.

It is important to understand what is going on with your well before you begin replacing pumps or drilling new wells. Sometimes it’s just a loose wire or a waterlogged pressure tank, other times you have much bigger problems.

Radionuclides in My Well Water- Now What Do I Do

A radionuclide is an atom with an unstable nucleus that emits its excess energy in the form of rays or high speed particles. Radioactivity, the release of the excess energy as gamma rays and high energy alpha and beta particles occurs when unstable elements give off the excess energy and particles to form more stable elements. The process by which an element changes from an unstable state to a more stable state by emitting radiation is called radioactive decay.
Gamma rays, alpha particles, and beta particles, which are given off by radioactive decay, have very different properties but are all ionizing radiation. Each form of ionizing radiations contains enough energy to break chemical bonds. The radiation can break bonds in DNA and RNA disrupting its function and potentially damage or destroy living cells. Alpha particles do not penetrate the skin but enter the body when alpha-emitters are in food, water, or air. While some beta particles are capable of penetrating the skin, beta emitters are more hazardous when they enter the body through food and water.

Radioactive elements are naturally present in rocks, soil, and water from trace amounts to dangerous concentrations depending on where you are. The occurrence of radionuclides in ground water is controlled primarily by the local geology and geochemistry of rock and the flow and age of the water. Research by the U.S. Geological Survey (USGS) found that the over time the concentration of a one radioactive element varied significantly from the same well. Migration and concentration of radionuclides depends on the amount of radioactive material in the bedrock, the moisture levels in the soil, groundwater circulation, and atmospheric pressure. Uranium, thorium, and radium can be highly mobile in groundwater and can move considerable distances and be re-deposited in soils or carried in the groundwater to the well. The isotopes of radium can enter the body through water, and some may be deposited in the bones and may over many years can result in an increased risk of getting cancer. Exposure to uranium in drinking water may result in toxic effects to the kidneys. Some people who drink water containing uranium over many years have an increased risk of getting cancer.

Variation in Radon concentrations over time from USGS

When dissolved in water, radionuclides are colorless, odorless, and tasteless, and typically cannot be detected by our senses, unlike many well water contaminants that cause an undesirable color, odor, or taste. Natural radioactivity in drinking water and its effect on human health have become a greater concern in recent years. The U.S. Environmental Protection Agency (EPA) has primary drinking water standards for gross alpha emitters, beta particles, radium and uranium under the Safe Drinking Water Act. However, the EPA also recommends that based solely on possible health risks and exposure over a lifetime that the goal should be to drink water containing a zero concentration of alpha emitters, beta particles, radium 226 and 228 and Uranium.

The EPA does not yet have a recommended drinking water standard for radon because the primary source of radon exposure is from breathing contaminated air in the home or office. EPA has focused on concentration of radon in the air. Radon is a colorless, odorless gas produced by the radioactive decay of radium, which in turn was formed by the decay of uranium. There is a correlation of elevated concentrations of radon in the inside air with elevated concentrations of radionuclidies in groundwater and groundwater can carry radon into the house.

Geological exploration has identified more than 55 locations within the Piedmont and Blue Ridge regions of Virginia where uranium is found. Uranium occurs in the Lovingston rock formation at a fraction of a percent, but radionuclides are known to be present in the groundwater in the regions thanks to sampling done at community water wells. About a decade ago, the USGS found that naturally occurring radionuclides in the ground water of southeastern Pennsylvania may pose a health hazard to some drinking water from wells drilled in the Chickies Quartzite. Counties in Maryland also have high radionuclides in water, just to name a few locations. You can find out more about the likelihood of radionuclides in your groundwater by inquiring at your state’s department of environmental quality or protection or by reading the community disclosure of nearby community water supply wells. That’s how I found out about local water quality and what to test for when I moved to this region.

If you are one of the 15% of U.S. households who obtain your water from a private well, you need to test your well. Every year you should test your well for bacteria and every few years for other substances including radionuclides. The radionuclides tests are expensive the cheapest way to go is to have a state and federal qualified and certified laboratory sample your well water for short-term GAPA, and GBPA. This screening test is less expensive than direct analysis for specific radionuclides. Testing for GAPA and GBPA may cost between $100 and $200, while testing for radium isotopes may cost between $200 and $300. Testing for total uranium may cost between $100 and $200. Call your local department of health to locate a qualified laboratory. Areas with known elevated levels of radionuclides tend to have a list of qualified laboratories. For a fee some health departments can sample your well. Nobody has the budget to test your well for free.

Once you identify the problem, solving the problem of radionuclides is very direct. The only real concern is drinking water and the possibility of radon carried in the water being released into the home. Reverse osmosis systems installed in the kitchen can be used to remove up to 99% of radionuclides in drinking water with selection of the correct membrane according to the EPA. Removal effectiveness depends on membrane selected, the water pressure and proper installation. Proper selection of the membrane and pressure is essential when selecting a reverse osmosis system. Hard water will cause scaling on the membrane so buy extra membranes and know how to change them. When the water pressure in the sink drops, the membrane is fouled and needs to be changed. The reverse osmosis systems require regular maintenance and monitoring to continue to function properly over an extended period of time.

Though I am not a fan of these systems in many applications, they are the best available technology for radionuclides. Reverse osmosis systems use a lot of water. They recover only 5% to 15% of the water entering the system, so they should only be used for the drinking and food preparation water. Waste water is typically connected to the house drains and will add to the load on the household septic system-it’s like adding an extra person to the septic load. A reverse osmosis system delivering 5 gallons of treated water per day may discharge 40 to 90 gallons of waste water per day to the septic system. This is a significant additional load and could impact the life and functioning of your septic system. You might want to look into other methods to dispose of the waste water.

Effectiveness of reverse osmosis system depends on initial levels of contamination, membrane size and type and water pressure. The application of pressure reverses the natural flow of the flow of water in osmosis from high concentration so that water passes from a more concentrated solution to a more dilute solution through a semi-permeable membrane. Reverse osmosis systems incorporate pre and post-filters along with the membrane itself in order for a reverse osmosis system to function properly. It is common to have a whole house filter system utilizing activated carbon installed in series with the reverse osmosis system. When addressing radionuclides the activated carbon filter can reduce the radon levels carried in the water, solving that problem.

Reverse osmosis units on the market range in cost from $200 to $3000 and vary in quality and effectiveness. Homes on well water need to purchase low pressure units. The size and membrane type are one of the factors that will determine cost. Replacement membranes cost $100 to $200 and filter cartridges around $50 (there are usually several)- it’s like a printer, the money is in selling the supplies. Reverse osmosis is a proven technology that has been used successfully on a commercial basis most famously for removing salt from seawater. Household reverse osmosis systems typically deliver small amounts (2 to 10 gallons per day) of treated water and waste 7 to 20 times the amount of water treated. Reverse osmosis systems can also remove many inorganic contaminants from household drinking water supplies including arsenic, sodium and nitrate. The removal effectiveness depends on the contaminant and its concentration, the membrane selected, the water pressure and proper installation and maintenance.

What to Do About Discolored Well Water After Heavy Rain

 In Virginia where I volunteer with VAMWON as part of the rural household water quality program run by Virginia Tech, it is estimated that 34% of the population obtains their drinking water from private groundwater wells, more than twice the national average. The most frequent call I get is for well water that turns suddenly brownish or discolored after a heavy rain. If you own a well, then the responsibility for ensuring that your family and friends are drinking safe water rests with you. While you cannot taste bacterial contamination from human and animal waste, nor nitrate/ nitrite contamination, brownish water after a heavy rain storm is an indication that you likely have one of two contamination problems with your well. Brownish or “dirty” water always associated with rain, is likely the fast infiltration of rainwater from the surface, but could also be caused by a nearby failing septic system that is overwhelmed by the rain.

After rust in the household fixtures there are five causes for well water to be discolored or brownish: surface infiltration, well collapsing or water level dropping, iron – iron bacteria and/or manganese in the water, pump system or well casing rusting and worst of all contamination from a nearby septic system. The likely causes of dirty looking water after heavy rains is surface infiltration, but contamination from a failing septic system is also possible and should be investigated. A bacterial test will confirm what your problem is. I would recommend taking a water sample to a local certified laboratory, and have the water tested for coliform bacteria and if positive e-coli and fecal coliform bacteria. However, there might not be a laboratory near your home in which case you could consider a home test. If your water is discolored after a heavy rains, take your sample while the water is discolored. If this is a local infiltration problem, the water will clear after several hours and could be bacteria free (but the bacteria could have infected the plumbing system and if you have it the water treatment system in the house. Event caused coliform bacteria do not always show up in every sample. They can be sporadic and sometimes seasonal when they occur in a water supply. Be concerned but do not panic if coliform bacteria are detected.

Coliform bacteria are commonly found in soil, on vegetation, and in surface water. Coliform bacteria also live in the intestines of warm-blooded animals and humans. Some coliform bacteria strains can survive in soil and water for long periods of time. Most coliform bacteria will not cause illness. However, because coliform bacteria are associated with sewage or surface waters, the presence of coliform bacteria in drinking water may indicate that other disease-causing organisms (pathogens) may be present in the water and the water supply is not sanitary. There are three different groups of coliform bacteria; total coliform, fecal coliform and Escherichia coli (E. coli) each has a different level of risk. Coliform bacteria do not occur naturally in most aquifers, but are mostly harmless. Fractured or creviced bedrock aquifers in Karst terrain that are close to the surface are the possible exception. Testing for e. coli and fecal coliform and nitrogen will differentiate the harmless coliform from contamination that is from surface infiltration of water from bacteria contamination that might impact your health and is from sewage or animal feces.

If your well tests positive for coliform bacteria and negative for fecal coliform and E. coli bacteria, you have an infiltration problem that may be persistent, but can be addressed and dealt with by the suggestions below. If your well tests positive for fecal coliform or E. coli your water is not safe to drink. Boiling the water will concentrate nitrogen that is commonly present with fecal contamination and can be lethal to infants. Call the Health Department. You are drinking water impacted from a septic system and the water is unsafe especially for children and the elderly. To make this drinking water safe the septic system must be repaired and/or a new well drilled. Public water systems routinely recycle water, but they have entire water treatment plants and constant water testing to address the problem.

From Penn State Cooperative Extension

Occasional impact from surface infiltration is a much more pedestrian problem. Bacteria washed into the ground by rainfall or snowmelt are usually filtered out as water seeps through the soil, so properly constructed water wells do not typically harbor Coliform bacteria. Surface infiltration of water is due to impaired pump, casing or well seal system. Often what fails in the typical 6 inch diameter pipe well with immersion pump is the grouting. Look at your well. A properly build and functioning well should not be impacted by rain, but wells get old and systems deteriorate. Items to look for and fix are:

• A missing or damaged well cap would allow rain to enter the well. Make sure to check seals around wires, pipes, and where the cap meets the casing may be cracked, letting in contaminants. A new sanitary sealing well cap can be purchased on-line or from a well driller. 
• Contaminant may be seeping through the well casing. Cracks or holes in the well casing allow water that has not been filtered through the soil to enter the well. This seepage is common in the wells made of concrete, clay tile, or brick. This can also happen to a steel pipe well that was hit by a piece of equipment such as a car, snow blower, lawn tractor or mower or that has rusted. A well driller can often install a sleeve to line the well casing. Wells installed in Virginia after 1992 (or in Prince William County since 1980) should have at least 40 feet of steel casing to protect the well from collapse and infiltration of shallow groundwater(less than 20-40 feet deep that may contain coliform bacteria. 
• Contaminants can enter the well by seeping along the outside of the well casing. Many older wells were not sealed with grout when they were constructed or the grouting has failed. Check the grouting carefully especially if water seems different after severe rains. Also, make sure that rainfall does not puddle against the well, but drains away. Repacking the soil might help.
• Well flooding is a common problem for wellheads located below the ground in frost pits that frequently flood during wet weather. Wells that are located in pits are commonly impacted by rain water pooling in the pit and entering the well. This can be corrected by having a well driller install an extension on the well pipe to raise the top, or create a drain for the pit. 

Hopefully, one of the simple items above will turn out to be your problem and can be quickly and easily resolved without need to drill a new well or install disinfection equipment. To use your well that has been impacted by coliform bacteria from storm related infiltration you need to chlorine shock your well after each rainfall until the problem is solved by one of the above suggestions, or you drill a new well. Yeah, I know what that costs, so temporary fixes are often necessary. Look, this is not the best idea, but it will disinfect your well each time it is impacted by surface infiltration. Water that looks dirty after a storm is a gross infiltration problem- there is a big leak somewhere, not the invisible coliform problem that is more easily addressed by an in-house disinfection system using either UV light or chlorine. Coliform bacteria are associated with warm-blooded animals, so they are normally found in surface water and in shallow groundwater (less than 20-40 feet deep). Most bacteria (with the exception of fecal and e-coli) are not harmful to humans, but are used as indicators of the safety (sanitary condition of the water.

The instructions below are standard procedure from various state department of health and the US EPA:

Run your hoses (away from your septic system and down slope from your well) to clear the well. Run it for an hour or three and see if it runs clear. If not let it rest for 6-12 hours and run the hoses again. Several cycles should clear the well. What we are doing is pumping out any infiltration within the well area and letting the groundwater carry any contamination away from your well. In all likelihood the well will clear of obvious discoloration. Then disinfect your well. This is an emergency procedure that will kill any bacteria for 7 to 10 days. After 7 to 10 days you need to test your well for bacteria to make sure that it is safe.

Determine what type of well you have and how to pour the bleach into the well. Some wells have a sanitary seal which must be unbolted. Some well caps have an air vent or a plug that can be removed. On bored or dug well, the entire cover can simply be lifted off to provide a space for pouring the bleach into the well.

Take one gallon of bleach of non-scented household liquid bleach and carefully pour the bleach down into the well casing using a funnel if necessary. Wear rubber gloves, old clothes and protective glasses to protect you from the inevitable splashes. After the bleach has been added, run water from an outside hose into the well casing until you smell chlorine coming from the hose. You can also use chlorine test strips for swimming pools to test for chlorine, but usually, the smell method works. Then turn off the outside hose. Now go into the house and one bathroom and sink at a time, turn on all cold water faucets, until the chlorine odor is detected in each faucet, then shut it off and move on to the next sink, or bathroom (if you have an automatic ice maker and water in your refrigerator dump the ice and run the water on the refrigerator also. If you have a water treatment system, switch it to bypass before turning on the indoor faucets. Once the inside system has been done, go back to the outside spigots and run the hoses until you smell chlorine coming out.

Wait 8 to 24 hours before turning the faucets back on. It is important not to drink, cook, bathe or wash with this water during the time period it contains high amounts of chlorine whose by products are a carcinogen. After at least 8 hours, run the water into a safe area where it will not kill your lawn, your trees or plants pollute lakes, streams or septic tanks. Run the water until there is no longer a chlorine odor. Turn the water off. The system should now be disinfected, and you can now use the water for 7 to 10 days when the effects of the disinfections wear off at that time test your well to make sure it is still safe to use. It is important not to run all the treated water into your septic system because the chlorine will kill all the bacteria in the septic system and the system will not function. This is the one time I might recommend adding bacteria to the septic system to account for any kill off that might occur from the minor amounts of chlorine treated water that was run through the plumbing system.

Final note. In the March 2012 Good Housekeeping magazine they evaluated home water testing kits. To test the home contaminant-detection kits, the Good Housekeeping Research Institute worked with the Water Sciences Laboratory at the University of Nebraska at Lincoln. Lab researchers spiked water samples with measured concentrations of contaminants the kits claimed to be able to detect, including two herbicides, nitrate, copper, lead, and bacteria. Then after following the kit's instructions, evaluated its performance at detecting the known contaminants. They found the PurTest kit to be the most accurate and easiest to use, but the second ranked First Alert test kit and the was also good and significantly cheaper. Make sure you test for both coliform bacteria and fecal coliform bacteria.