Buying Good Water- a House with a Well

For most of the first 25 years of our marriage we lived in rental apartments. We talked about someday owning a house. My husband wanted a big house on lots of land in Virginia, his home. I generally dreamed of a house of more modest size near whatever city we were living in at the time.  After living a decade and a half in California with constant water restrictions and crisis, water became the number one item on my list (followed by high-speed internet). So, we ended up in Virginia in his someday house with a well with my water supply.

There is a whole lot beyond being clear and tasting good that makes water satisfactory.  The first thing to verify is that the well is constructed properly. That is fairly simple, though there are no national standards for construction of private water wells, in Virginia the Department of Health well construction regulations went into effect in 1992. So, buy something with a well drilled after that.  A simple trip to the local health district allowed me to get the well completion report for all the houses we were considering.  Well built to current standards-check.

The well completion report  tells you how old the well is, how deep, what the well yield was at completion. I was also looking for a well with a stabilized yield greater than 6 gallons a minute in the right kind of geology because geology impacts how a well ages. If you are buying an older well (still built after 1992) check the water level and yield - yield diminishes over time. You will have to hire a well driller to do this. 

There are three considerations for a private well- the well and well system, the water quality and the water quantity. Failure in any of these can impact your life and the value of your home. The well is essentially a hole in the ground. Shallow wells (those less than 50 foot deep) are  dug or bored into the ground and have larger diameters (2-4 foot). Shallow wells are more prone to contamination and drought and bored wells have the shortest life. Deeper wells are called drilled wells because they are drilled into the ground to depths from 50-450 feet or more and because of the need for drilling rigs cost much more to build. The diameter of a drilled well is 6-8 inches. 

Only buy a home with a drilled well. Generally, drilled wells provide a safer source of drinking water, and are less often impacted by drought. In igneous and metamorphic rock systems like the Piedmont of Virginia, the fractures and fault lines formed in the rocks store and transmit groundwater. The size and number of water bearing fractures varies and there is a wide variation in well yields from under 1 gallon per minute to over 50 gallons a minute depending on location and specific site geology. Fractures can become fouled with mineral deposits or iron bacteria or simply go dry over time. 

Aquifers can go dry unexpectedly, but all wells will fail over time. The lifespan of a drilled well is assumed to be 20-50 years, but varies tremendously based on site specific conditions. I personally know of a drilled well that lasted 65 years, but if you are buying a home with a well over 20 years old you will need to budget for drilling a new well. Make sure that the cost is considered and that the property has another location to drill a well.  

The well system consists of the well, the well casing, the inlet for water, and the pumping system. The casing is the structure around the well hole to prevent its collapsing. It could be a steel or plastic casing or an open hole in the bedrock. In this part of Virginia, the Piedmont, the top of the well is lined with steel for 50 feet and then the well is open in the bedrock allowing the water to flow into the well. A steel well casing will rust over time and eventually collapse. The well casing should be 1-2 feet above the land surface to make sure that during storms and flooding that nothing washes down the well. There should be no holes or cracks in the visible portion of the casing and the well cap should be tightly bolted closed.

The essential components of a modern drilled well system are: a submersible pump, a check valve (and additional valve every 100 feet), a pitless adaptor, a well cap, electrical wiring including a control box, pressure switch, and interior water delivery system. There are additional fittings and cut-off switches for system protection, but the above are the basics and each and every component must work properly for your well to function properly.

The pumping system includes the pump, piping and electrical connections to pump water from the well into the house and a pressure tank to maintain constant water pressure in the house. Shallow wells usually use centrifugal pumps and are often located in a pump house or the basement. Drilled wells have submersible pumps. The pump and pumping systems are the most likely components to fail in a well. The average life of a submersible pump is variously reported as 12-15 years, but many pumps fail in the first few years. 

In addition, in order for a well to keep supplying water to your home the components within the basement must all continue to work. These components provide constant water pressure at the fixtures in the house and the electrical switch that turns on the pump. For a drilled well if there is any other equipment beyond the pressure tank, it is a water treatment system, and you need to test the water before and after the treatment. 

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. 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. Bladders and electrical switches will fail over time and valves and switches and impellers on the pump can break, foul or find any number of ways to fail. You have to assume that pump systems that are older than 12 years are on borrowed time. It does not mean that a pump system cannot last 25 years or more, but I would not bet on it. 

When buying a home with your own water supply you need to consider the construction, condition, age and location of the well in addition to water quality and quantity. Geology plays an important role in the water quality and quantity.  Clay loams or silty clay soils filter pollutants and protect an aquifer. A shallow water table and fractured bedrock may provide larger quantities of water, but the shallow fractured rock systems are susceptible to contamination from the surface. 

The specific geology and water quality will determine the life span of a well. So pick your desired geology. Within the three counties around here there are significant variations in the geology. There is an area in Loudoun County that is high in iron and an area nearby that is karst terrain. The groundwater in karst terrain is easily impacted by surface contamination and is potentially subject to sinkholes. No. There are areas with very high natural iron and manganese content, areas of extremely hard water and areas with soft or aggressive water. No, no and no.

Within Prince William County Virginia there are several distinct geologic provinces that will have different groundwater characteristics. 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. In other parts of the county there are deep wells in the diabase that tend to have reliable lower yields. I choose fractured siltstone as my targeted geology. 

The issue of whether water is safe to drink is separate from whether the water is free of unpleasant contaminants like iron, manganese, chloride, and low levels of hydrogen sulfide or the groundwater has been contaminated. The well must be tested. Before you buy test the water for all primary and secondary contaminants in the Safe Drinking Water Act. In addition to testing the water for any nearby likely sources of contamination. I was only interested in purchasing a home with water that did not need any treatment. There is a big difference to me between fixing a problem that develops over time and buying that problem. 

Water chemistry is a tough category to give rules of thumb. Your best option is to do a broad scan of the well water quality. There are screening packages available from U.S. EPA certified laboratories like  National Testing Laboratories that screen water wells for all the primary and secondary contaminants in the Safe Drinking Water Act.

The WaterCheck with pesticides package from National Testing Laboratories is a broad stroke test, testing the water for 103 items including Bacteria (Total Coliform and E-Coli), 19 heavy metals and minerals including lead, iron, arsenic and copper (many which are naturally occurring, but can impact health); 6 other inorganic compounds including nitrates and nitrites (can indicate fertilizer residue or animal waste); 5 physical factors including pH, hardness, alkalinity; 4 Trihalomethanes (THMs) and 47 Volatile Organic Chemicals (VOCs) including Benzene, Methyl Tert-Butyl Ether (MTBE) and Trichloroethene (TCE). The pesticide option adds 20 pesticides, herbicides and PCBs.  This testing can be done for a few hundred dollars.    

The report they produce tell you if the contaminant was detected, if detected if it was below or above the EPA standard under the Safe Drinking Water Act, and finally if the contaminant was above the standard if it was above an enforceable MCL (maximum contaminant level). If sodium is present it should be under 10-20 mg/L. Any higher and you have salt water infiltration or the well system might have a water softener that is obscuring many of your results and you need to test again ahead of the water treatment. The nitrate level should be well below the EPA standard of 10 mg/L closer to the background level (around 2 mg/L in northern Virginia). Higher than 5 mg/L tends to be related to septic performance either at your house or a neighbors but can also indicate historic use of fertilizers or animal waste storage. If these problems exist, it will only grow worse with time.

I like hard water so anything between 100 mg/L and 180 mg/L is fine by me. Higher though, could be difficult to live with and should be avoided. Too low and you might have aggressive water (slightly acidic) which has a whole bunch of other problems or once more a water softener is installed and you need to retest.  

All trihalomethanes, solvents (organic volatiles) and hydrocarbons should be non-detect. None of these are naturally occurring and even low levels are an indication of a source of industrial contamination. A trace of TCE in a well was the first symptom of what turned out to be a Superfund site in Loudoun County. Run away. Same is true for the pesticides and other organic analytes. 

Metals (inorganic analytes which are naturally occurring) should all be on the low end of the allowed range, except for lead which should be non-detect after the first flush. There is no safe level of lead and it is not naturally occurring in groundwater. Cadmium, lead and mercury are metals that are found at relatively low concentrations in the environment. Lead is nearly immobile in soil so it does not enter groundwater by any natural pathway. It generally appears from the deterioration of metal plumbing and well equipment that contains low levels of lead. Lead in groundwater can also be a result of industrial contamination. Run away very fast. 

You are Responsible for Your Well Water

Although the majority of the United States' population gets its drinking water from pubic systems, the Environmental Protection Agency, EPA, estimates that more than 23 million households rely on private water supply system (i.e. wells, springs, and cisterns) for drinking water. Most of these are private wells. My own home is supplied with water from a drilled well. EPA does not regulate private drinking water systems- your on your own in making sure the water in your home is safe to drink.  Many states have well regulations, the vast majority of which are construction standards for new wells.

The concentration of private wells is not evenly distributed throughout the country, obviously private wells tend to be in rural or semi-rural areas. The Census Bureau stopped collecting information specific to private well use in 1990, so much of the national data is extrapolated from 1990. Virginia Tech reports that over 22% of the Virginia’s population or 1.7 million people are dependent of private drinking water wells for their drinking water.

The quality and safety of private domestic wells, are not regulated under Federal or, in most cases, state law. In Virginia only the construction is regulated and wells are only required to demonstrate the absence of bacteria, the most basic form of potability at the completion of the well construction process. The U.S. Environmental Protection Agency Safe Drinking Water Act (SDWA) does not regulate individual households.

As a result, individual homeowners are solely responsible for maintaining their domestic well systems and for any routine water-quality monitoring that may take place. Just because your water appears clear doesn’t necessarily mean it is safe to drink. You cannot taste bacterial contamination from human and animal waste, nor taste nitrate/ nitrite contamination. Many chemical contaminants cannot be tasted or smelled at levels that can impact your health. Since bacterial contamination cannot be detected by taste, smell, or sight, all drinking water wells should be tested at least annually for Coliform bacteria and E Coli. Testing is the only way to detect contamination in your water.

In the past it was not recommended to test your well, it is now widely recommended (by the department of health and University Extension programs) that private well owners test their wells annually (at least for bacteria), yet the vast majority of well owners still do not. Private well owners often lack a basic understanding of the groundwater that supplies the wells and the mechanical components of their well systems and turn a blind eye to maintaining their water systems.  

Groundwater comes from rain, water and snow melt percolating into the ground. Typically, the deeper the well the further away is the water origination and the older the water. The groundwater age is a function of local geology, the amount of precipitation and the rate that water is pumped out of the aquifer. Geology also determines the ease with which water and contaminants can travel through an aquifer; microorganisms in the soil and from wildlife and spilled chemicals or contaminated runoff can travel into groundwater supplies through cracks, fissures, and other pathways of opportunity like fractured rock systems. The land surface through which groundwater is recharged must remain open and uncontaminated to maintain the quality and quantity of groundwater.

The quality of your water will be determined of the source of the groundwater, the ability of your local geology to protect or impact your aquifer and the absence or presence of a potential local source of contamination. First of all let me say that according to the US EPA actual events of groundwater contamination have historically been rare and typically do not occur at levels likely to pose significant health concerns. This fact is the basis of the EPA and state health departments’ acceptance of private and unmonitored use of groundwater for drinking water purposes for a significant portion of the United States. However, as population density increases and we use more and more chemicals, pesticides and drugs, there are more opportunities to contaminate our groundwater. Because I am a retired environmental engineer I tend to focus on threats to the groundwater and worry about my groundwater quality more than most.

The most common sources of pollution to groundwater supplies come from two categories; naturally occurring ones and those caused by human activities. Naturally occurring contamination are produced from the underlying soil and rock geology. Microorganisms in the soil can travel into groundwater supplies through cracks, fissures, and other pathways. Nitrates and nitrites from the nitrogen compounds in the soil can also enter the groundwater. From the underlying rocks radionuclides and heavy metals can enter the groundwater. There are areas with natural occurring arsenic, cadmium, chromium, lead, selenium and fluoride. While many natural contaminants such as iron, sulfate, and manganese are not considered serious health hazards, they can give drinking water an unpleasant taste, odor, or color.

Human activities can also introduce contaminants into the groundwater. Bacteria and nitrates can be caused by human and animal waste. Improperly constructed and sealed wells can allow surface contamination to enter the well. Improperly maintained septic systems containing human waste and any chemical you flush down the drain, horses, and backyard poultry can contaminate the groundwater. Leaks from underground storage tanks, surface disposal of solvents, motor oil, paint, paint thinner, or nearby or historic landfills or industrial operations can contaminate groundwater. A confining geological layer can protect groundwater from surface contaminants more effectively than a fractured rock system or sand and gravel, and there is very limited natural protection in karst terrain. In Virginia, where there are rich supplies of groundwater our aquifers can be very susceptible to contamination in certain locations.

Often well owners lack access to objective information and a framework for understanding problems and help in solving the problems with their wells.  Because private drinking water wells serve more than a fifth of its population, Virginia  has taken steps to assist private well owners monitor, understand and maintain their wells. The Virginia Household Water Quality Program (VAHWQP) was created by the Virginia Cooperative Extension to provide affordable water testing and education about private water wells to residents of the Commonwealth. For $65 samples are analyzed for: iron, manganese, nitrate, lead, arsenic, fluoride, sulfate, pH, total dissolved solids, hardness, sodium, copper, total coliform bacteria and E. Coli bacteria. These are mostly the naturally occurring contaminants and common sources of contamination: a poorly sealed well or a nearby leaking septic system, or indications of plumbing system corrosion. Though this is not an exhaustive list of potential contaminants, these are the most common contaminants that effect drinking water wells. Though Prince William's clinic was in the spring, Loudoun, Fairfax, Culpeper and Fauquier Counties are are all having clinics this fall. You should make a point to participate in the program. It is an easy way to check your well every year.

The Wells of Virginia 2021

Private drinking water wells serve more than a fifth of Virginia’s population or 1.7 million residents.   Virginia created the Virginia Household Water Quality Program (VAHWQP) to provide affordable water testing and education about private water wells to those residents of the Commonwealth. Extension Offices hold drinking water clinics and provide information to assist private well owners in understanding and maintaining their wells. 

The quality and safety of private wells are not regulated under Federal nor, in most cases, state law. In Virginia regulations control only construction and the absence of bacteria at the time of a well’s completion. The U.S. Environmental Protection Agency Safe Drinking Water Act does not regulate individual households. As a result, individual homeowners are responsible for maintaining their own water supply and ensuring the quality of the water for their family.

The Virginia Household Water Quality Program was, originally created in 1989, was relaunched in 2007 with a USDA grant. In 2011 the program was expanded under another USDA grant to subsidize testing, quantify bacteria, add metals, and begin research out of Virginia Tech. Now the program is self-sustaining with clinics held in 91 of the 96 counties in 2021. The analysis is done by the Virginia Tech laboratory and research utilizing the data is being pursued by graduate students.

In all the Virginia Household Water Quality Program clinics the water samples are analyzed for: iron, manganese, nitrate, lead, arsenic, fluoride, sulfate, pH, total dissolved solids, hardness, sodium, copper, total coliform bacteria and E. Coli bacteria, and last year cost $65 in Prince William County. These are mostly naturally occurring contaminants and common sources of contamination: a poorly sealed well or a nearby leaking septic system, or indications of plumbing system corrosion. Though not an exhaustive list of potential contaminants, these are the most common contaminants that effect drinking water wells.

Though about 600,000 of Virginia households with 1,700,000 residents or 22% of the Virginia population have private wells, only around 2,785 households chose to participate in the Virginia Household Water Quality Program clinic in 2021 and may not be representative of all private drinking water wells in the Commonwealth. Nonetheless, the data collected over the past 15 years is the one of the largest databases on private drinking water wells available. Well water quality is driven by geology, well construction and condition, nearby sources of contamination, and, within the home, water treatment devices and composition of plumbing materials.  

from Virginia Tech: contaminants found above the SDWA limit

Overall, the statewide sampling last year found that just under 40% of the wells have coliform bacteria present, and almost 6% have E. coli bacteria. Though 22% of wells were found to have acidic water (low pH) about 6% of homes have first flush lead levels above the EPA safe drinking water standard maximum contaminant level for lead and copper. Lead and copper leach into water primarily because of corrosion of plumbing and well components but can also result from flaking of scale from brass fittings and well components unrelated to corrosion. Copper and lead predominately come from the pipes. Over time older pipes and fixtures corrode or simply wear away and the lead and other corrosion material (like rust) is carried to the drinking water. Time and water do cause corrosion, but this can be aggravated by the pH of the water or other changes in water chemistry. The amount of lead corroded from metal plumbing including faucets with brass interiors generally increases with increasing water corrosiveness.

About 36% of households have elevated sodium exceeding the EPA Safe Drinking Water Act limit. This could be a result saltwater infiltration from natural or man-made sources (like road salt) or could indicate that water softeners are adding too much sodium to the water. Of the 2,785 participants in 2021, 41% report that they NEVER tested their water before and 32% had tested only once (presumably at purchase). About 43% of participants have participated in the VAHWQP clinic before.  Virginia Tech recommends annual testing of well water to make sure it is safe to drink, and you have the appropriate treatment system(s).

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.

10 Rules for Buying a Home with a Well and Septic System

Well and septic systems are simply mechanical components to a house. What makes them different is that they are specifically excluded from home inspections, are very expensive to replace and essential. There are times and instances that a well or septic system has no good replacement location and then the home owner has a large problem on their hands that will cost tens of thousands of dollars to solve. Make sure that you do not buy someone else’s problem and make it your own.  When shopping for a home, there are some “fatal flaws” that can quickly and easily be identified. This is the list of quick observations and the reasons they might be a problem for a well and septic system to quickly eliminate properties as potential big problems, require further investigation or to factor the price of repair or replacement into an offer on a house. (For updated articles on this topic see "The House has a Well...") 

1.      The house must have 2-3 acres of land.

2.      Do not buy a home with a dug or bored well.

3.      The visible well should be a 6 inch diameter pipe with a bolted cap sticking a foot out of the ground.

4.      Water from the road, driveway, and downspouts should not drain to the well.

5.      Rainwater should flow away from not to the wellhead.

6.      If the well was drilled before 1992 don’t buy the house.

7.      The well head must be at least 100 feet from the nearest edge of the septic drainfield and any backyard chicken or poultry yards and coops. 

8.      The well head must be at least 50 feet from the nearest corner of the house.

9.      Ask to see the maintenance records for the septic system and well along with water test results (having records is an indication of proper maintenance).

10.   When you make an offer on a house a satisfactory water test and a professional septic inspection should be included in your contingencies.

This is what a drilled well looks like

The well and septic system should be easily identified and pointed out. A well should be a 6 inch diameter pipe with a bolted cap sticking a foot or more above the ground surface. What I have described is a drilled well there are also dug and bored wells. Do not buy a home with a dug or bored well. Those types of wells fail sooner, are prone to go dry during droughts and because they are shallow (less than 40 feet deep) are more subject to pollution. Drilled wells are more than 40 feet deep, typically more than 100. In Virginia well drillers are required to file a drilling log with thecounty and comply with drilling regulations since 1992. If the well was drilled before 1992 don’t buy the house unless you have factored well component replacement into the price and you should be thinking about the costs and possibilities of well replacement.  While many wells will last decades, it is reported that 20 years is the average age of well failure. Older well pumps are more likely to leak lubricating oil or fail. Well casings are subject to corrosion, pitting and perforation. Septic drainfields also have a limited life. The life of a septic drainfield is dependent on how the system is managed, the frequency of septic tank pump outs, and the number of people living in a house, but 20-30 years may be the life of those systems, too.

If a property has a well and septic system and has less than 2-3 acres, do not buy it. This is simple there will not be enough room for a replacement well and septic system when the time comes (all systems fail eventually) and the well is likely to be too close to the home’s own or the neighbor’s septic system. The most common contamination problem for a well is an adjacent septic system and research done in Duchess county New York identified density of septic systems as an easy indicator of nitrate contamination to groundwater. The Dutchess County study and another study performed in North Carolina found that overall average density of on-site waste disposal (traditional septic or alternative) should not exceed one unit per 2-3 acres for an average size house to ensure water quality and recharge in groundwater supplies. The controlling factor in minimum lot size requirements in the northeast appears to be maintaining water quality, not groundwater recharge. Adequate dilution, soil filtration and time are necessary to ensure sustainable water quality. It is often surprising how close to a private well the recharge zone is.

Failed drainfield. Picture from NC Health Department

 So, while you are walking around outside make sure that the well head is at least 100 feet from the nearest edge of the septic drainfield and 50 feet from the nearest corner of the house. It can often be difficult to identify a septic drainfield while walking in the yard. Newer systems often have plastic caps to the distribution valve, but older systems often do not- the distribution valve is buried. In Virginia (and most places) if a well is more than 100 feet deep the septic leach field need be only 50 feet away, but there are many wells like mine that have more than one water level and the shallower one is less than 100 feet deep (in my case 46 feet) making the well much more susceptible to contamination for the septic effluent leaching into the ground. If the well is too close to the drainfield, move on to the next house in your search, the well could too easily be impacted by the septic drainfield.

The final treatment for all septic systems is septic system effluent (after any intermediate treatment steps in an alternative system) is filtering of the wastewater through the soil. The method of sewage treatment with a septic system is soil organisms and soil filtration and adsorption. Whatever was flushed down the toilet or poured down the drain over the years has found its way into the drainfield and potentially to the groundwater. Not only should the well head be at least 100 feet from the nearest edge of the drainfield, the drainfield should be downhill and down gradient for the well. The land that my house sits on has a predominately southeast slope to the river at the bottom of the property. It is a fairly safe bet that the groundwater flows with the land topography towards the river.  

Two septic tank lids and filter for alternative septic system. 

Look for the septic tank. The tank should not be entirely buried and at least one port should be visible in the yard. If the tank is entirely buried- move on, do not buy the house because it is a safe bet that the tank has never been pumped and the entire septic system will have to be replaced.  The solids, scum and grease that accumulate in the septic tank need to be pumped out and disposed of every few years. If not removed, these solids will eventually overflow the septic tank, accumulate in the drain field, and clog the pores in the soil and the openings in the pipes. While some clogging of soil pores occurs slowly even in a properly functioning system, excess solids from a poorly maintained tank or a tank where enzyme additives were used instead of pumping the tank can completely close all soil pores so that no wastewater can flow into the soil. The sewage effluent will then either back up into the house, flow across the ground surface over the drain field, or find another area of release in the septic system. In some cases where the drain field has become clogged and no longer can adequately absorb the wastewater, the toilets and sinks might not drain freely. A black residue may remain at the bottom of the toilet.  If the drain field can absorb the effluent, but no longer treat it, the sewage may contaminate the groundwater or surface water with fecal coliform bacteria. On a dry day if there is a soggy area of the yard the drainfield may already be failing.

The reason a well should be more than 50 feet from a house is that in Virginia (and many other locations) building codes require that a construction site be pretreated for termites, and many homeowners spray gallons of pesticides into the ground to treat or prevent termites.  (There are other approaches to termite management, but most homeowners do not use them. Termite bates are easy to spot in the yard and indicate that chemical barriers are not used. ) http://greenrisks.blogspot.com/2011/10/low-impact-termite-management.html The most popular professionally applied conventional chemical treatments on the market are Premise (imidacloprid), Termidor (finpronil), and Phantom (chlorfenzpyr). These chemicals range from slightly toxic to very toxic and vary in their solubility and affinity for soil. They are less environmentally persistent and more rapidly biodegradable, than previous generations of chemicals. This all means that they breakdown faster and do not last as long, but also may allow their breakdown products to migrate to the shallow groundwater.

Sentricon termite bate station

Other posts:
https://greenrisks.blogspot.com/2019/06/what-to-know-when-buying-home-with-well.html
https://greenrisks.blogspot.com/2020/03/what-to-know-if-buying-house-with-well.html