You Should Regularly Chlorinate Your Well

 It is common practice to “clean” public supply wells on a regular basis. This is often because of an observed decrease or loss of chlorine residual in treated wells which can allow contaminant entry into the well system. This is often caused by sediment or biofilm build-up within the well. Preventive maintenance is to chemically treat and flush the production well.  This need to regularly treat a well to prevent biofilm buildup and mineral encrustation has been well known and practiced for decades in small systems. However, this has not been the practice in private water well. That is beginning to change.

The last time I heard Brad White a groundwater geologist from the Virginia Department of Environmental Quality Office of Ground Water Characterization give a talk on the work DEQ was doing in Fauquier County, he happened to mention that in every well he put a camera down he had observed iron bacteria.

From Penn State Extension: “As a water well ages, the rate at which water may be pumped tends to decrease.” Penn State attributes this decrease in performance of a well to incrustations and biofouling of well screens and rock fractures or borehole, saying: “In severe cases, the obstruction to flowing water can render the well useless. Major forms of incrustations can occur from build-up of calcium and magnesium salts, iron and manganese compounds, or plugging caused by slime producing iron bacteria or other similar organisms (bio-fouling).”

The Provincial Government of Alberta (Canada) says indescribing iron bacteria: “This slime will coat the inside of the well casing, water piping and equipment, creating problems such as reduced well yield, restricted water flow and red staining of plumbing fixtures and laundry. However, all iron- staining problems are not necessarily caused by iron bacteria. The iron naturally present in the water can also cause significant problems.” There are all sorts of odd problems that are caused by iron bacteria. Over time many wells develop these problems. These harmless bacteria can foul a well, damage pumps, stain plumbing fixtures, clog pipes, faucets, showerheads, and produce unpleasant tastes and odors in drinking water. Yet, water is very rarely tested for iron bacteria since very few certified laboratories conduct the test. 

Yet, private well owners typically try to treat the symptoms rather than the cause of the problem. Elimination of iron bacteria once a well is heavily infested can be difficult. Iron bacteria cannot be eliminated by most common water filtration methods or water softeners. Iron bacteria will foul that equipment.  However, though it is difficult to eliminate, it is actually very easy to control – just oxidize the heck out of the well. This is accomplished by chlorine shocking of the well with adequate chlorine concentration and several hours of mixing accomplished by recirculation.  

Thus, routine maintenance of a private water well should include regular chlorination to control biofouling of the well and maintain water quality. Personally, I chlorinate my own well on even number years to prevent the buildup of a biofilm in my well and plumbing system and maintain the aesthetic quality of my water. I drain and flush the hot water heater annually to protect it from biofilm and mineral buildup and keep the temperature above 140 degrees.  If you have treatment equipment like a water softener, you might want to consider chlorinating your well annually and treating your media to prevent a bio mat from forming in the media tanks.

There are so many things that regular chlorination will solve or prevent that you might want to consider it a regular part of home maintenance. Even if you do not chlorinate your well regularly, you should chlorinate your well when:

• the well is new
• the well has been repaired
• the well has been flooded
• the well exposed to bacterial contamination in another manner, such as a crack in the well cap  

In addition, you should test your well for bacteria each year, usually in the spring (or the wet season), and if there is any change in the taste, color or odor of your drinking water. A confirmed positive test for coliform bacteria requires disinfection at the least.

Where does the Lead in Wells Come From

In 2012, the Macon County Health Department in North Carolina discovered county-wide water lead contamination in private wells due, they reported, to corrosion of galvanized well components. In North Carolina current well construction code requires the installation of a tap on the well; thus, they were able to differentiate lead contamination originating from household plumbing and lead contamination originating from the well.

They found "first draw samples" collected at the wellhead between 2008 and 2012 documented that 55 of 398 (14%) of newly constructed wells exceeded the U.S. Environmental Protection Agency Lead and Copper Rule action level for lead of 15 μg/L. However, there is no safe level of lead exposure, as even low water lead levels-those less than 5 μg/L- can increase a child's blood lead level. In the Macon County Health Department samples they found water with lead concentrations as high as 191 μg/L.

North Carolina like most of the eastern seaboard states has areas at high risk for corrosive water. During periods of stagnation, in water that is corrosive (with a pH less than 6) a chemical redox reaction occurs that dissolves and leaches lead into the water. Lead present in well and plumbing components is leached into the water. This lead comes from brass fittings and galvanized pipe (which has a lead- zinc coating), and plumbing components produced before 2014 when "lead-free" fixtures could have up to 8% lead. In Virginia, the Blue Ridge, Piedmont and shallow wells in the Coastal Plain have a high risk for corrosive water and lead contamination in their water.

Civil and Environment Engineering Department at Virginia Tech and the Environmental Health Services Branch of the Macon County Public Health Department and lead by Kelsey J. Pieper PhD USDA-NIFA Postdoctoral Fellow at Virginia Tech investigated lead in well water concentrations at the homes of 15 private wells in Macon County found to have elevated levels of lead in their wellhead samples. There was another part of the research but we will not discuss that here.

 Low pH water can corrode metal plumbing fixtures causing lead and copper to leach into the water and causing pitting and leaks in the plumbing system. The presence of lead in pipes and fixtures becomes a bigger problem with water with a pH less than 6. In the past lead was used to solder copper pipes together before 1988 when the 1986 ban on lead in paint and solder went into effect. Also, until 2014 when the 2011 Reduction of Lead in Drinking Water Act went into effect, almost all drinking water fixtures were made from brass containing up to 8% lead, even if they carried a plated veneer of chrome, nickel or brushed aluminum and were sold as "lead free." So even home built with PVC piping in the 2000's may have some lead in most of the faucets.

The pattern of lead release and remediation for lead contamination originating from plumbing have been extensively studied. The goal for the Virginia Tech and the Macon County Public Health Department study was to identify patterns of lead leaching/ release within the well itself. Plumbing components used within a private well are not subject to the 1986 Lead Ban or the 2011 Reduction of Lead in Drinking water Act requirements. Galvanized iron is still commonly used for well casings and fittings and drop pipes in well deeper than 600 feet. Before 2014 Prime Western grade “lead free” galvanized steel zinc coating was required to contain between 0.5%-1.4% lead. After 2014, “lead free” galvanized steel have less than 0.25% lead in the surface coatings. Nonetheless, under corrosive conditions, any lead used in coatings can be easily released to the water and pumped to the household tap or accumulate in scale layers on the pipe surface or well bottom where scale can accumulate and be released or picked up and pumped with the water.

Water lead concentration patterns and sources of contamination within the wells differed among the 15 private wells as can be seen in the diagrams below which come from Environmental Science and Technology article cited below. The scientists found that elevated lead was associated with three sources of lead release: (1) dissolution of lead from well plumbing during periods of stagnation; (2) scouring of leaded scales and sediments along the well plumbing infrastructure during initial water use; and (3) mobilization of leaded scales during continued water use.

From Pieper et al.

As you can see, water lead levels measured during well testing show that in (A) nine wells had no water lead during continued water use however, (B) six wells showed sporadic spikes in particulate lead during continued water use. The detection limit of lead in the analysis was 1 μg/L. Lead contamination in a well can come from three potential sources; galvanized iron well casings, galvanized iron and brass well components, and leaded scales and sediment which have formed over time.

Corrosive water is the primary risk for lead in well water. However, over time water with a neutral pH could dissolve the coating on galvanized iron and in brass well components. The well completion reports do not document materials used for well components in Virginia or anywhere else to my knowledge. Once installed a well casing cannot be removed. It is possible to line the casing with a plastic pipe a technique used to seal a well where the grouting has failed. All the other components of the well can be replaced, though excavation would be required to replace the exterior portions of the pitless adaptor. However, scale that has accumulated on the bottom of the well might remain a source of lead if it is not mechanically removed. Further research needs to be done to further characterize the lead in well and effective remediation techniques.

To read the complete article:

Elevated Lead in Water of Private Wells Poses Health Risks: Case Study in Macon County, North Carolina

Kelsey J. Pieper, Victoria E. Nystrom, Jeffrey Parks, Kyle Jennings, Harold Faircloth, Jane B. Morgan, Jim Bruckner, and Marc A. Edwards Environmental Science & Technology 2018 52 (7), 4350-4357 DOI: 10.1021/acs.est.7b05812 

Private Wells and Health Risks in Your Drinking Water

Private wells do not fall under the regulatory authority of the U.S. Environmental Protection Agency (EPA) or the Safe Drinking Water Act. In the past it was always assumed that groundwater that supplies private wells is fairly safe and clean. However, recent research by the U.S. Geological Survey and studies of water borne disease outbreaks associated with untreated groundwater have found that private wells, springs and cisterns are a potential source of elevated health risk. In addition, while waterborne disease outbreaks overall have fallen since 1971, the waterborne disease outbreaks in private well systems continues to increase relative to public systems.

This is of concern because according to the EPA, approximately 15% of U.S. households, more than 47 million people get their drinking water from private wells and springs.

Preliminary efforts to survey water quality in private systems in limited studies in Pennsylvania, Wisconsin and Virginia report that 23−58% of wells tested in their studies exceed at least one safe drinking water act health-based standard. However, since 2010 Virginia has been operating the subsidized well water testing clinics as part of the Virginia Household Water Quality Program testing wells throughout Virgininia. The goal of the Virginia Household Water Quality Program is to educate well owners, improve the water quality and protect the health of Virginians with private water supplies, such as wells, springs and cisterns. In 60 of Virginia’s 95 counties more than half the households rely on private wells, springs, and cisterns. In total there are more than 1,500,000 households in Virginia with private water supplies.

The Virginia Cooperative Extension obtained a grant from the U.S. Department of Agriculture’s Cooperative Research Education and Extension Service to restart the Virginia Household Water Quality Program originally launched in 1989. Working with the researchers at Virginia Tech the program has used the data they have collected to identify characteristics in wells within counties and throughout the Commonwealth. In the 2012 clinics analysis for lead and copper were added. Participation in the drinking water clinics is voluntary and though the analysis is subsidized, participants are still charged a fee, currently $55. Homeowners who wish to participate have to hear about the clinic, show up for two meetings, purchase a water sampling kit with instructions and are asked to fill out a questionnaire about system characteristics, perceived water quality and household demographics and drop off their samples on time on the scheduled day. Typically, better educated and more affluent households participate.

The scientists at Virginia Tech have used the data from the 2012 clinics and targeted additional field study to examine, lead in drinking water from private wells. The following information is from their recent paper cited below.
Of the 2,146 samples taken in an 18 month period from spring 2012 to fall 2013, 58% of the wells sampled exceeded at least one Maximum Contaminant Level (MCL) from the EPA’s safe drinking water act’s levels though only 14 of the 82 parameters were tested. Bacterial contamination was the most common issue, with 46% of systems testing positive for total coliforms with 10% having E. coli present. The most common treatment systems were water softeners which are used to treat hard water, elevated iron and manganese which were found to be less prevalent that water softener sales would indicate.

Using the action level for lead and copper as a threshold, 19% of the tested systems had elevated lead concentrations (15 μg/L) and 12% had elevated copper concentrations (1.3 mg/L) in the first draw. Lead leaches into water primarily as a result of corrosion of plumbing and well components. Corrosion control techniques such as adjusting pH or alkalinity that are commonly used in public systems are not common in private wells where the decision to install and maintain treatment is solely the prerogative and responsibility of the homeowner. As a result, though 26% of the private wells had pH outside the neutral range of 6.5-8.5 (and 89% of these were below 6.5), only 5% of private well systems had acid neutralizers installed to control pH and corrosion within the home and 3% had reverse osmosis units that could remove lead among other contaminants. 

The scientists did not find a correlation between self-reported well depths and lead concentrations, but lead concentrations were negatively correlated with pH values. The lower the pH (more acidic the water) the higher the lead concentrations found. Houses built before 1988 when the ban on lead went into effect had higher lead concentrations; however, it is important to note that elevated lead concentrations were still found in homes built after 1988. The scientists attributed this to the presence of lead in brass fixtures and faucets. If that is correct, then with the ban on lead containing materials in the Reduction of Lead in Drinking Water Act, lead release from brass components should be reduced in the future.

For most of the private well supplied systems sampled in this study, flushing for 5 minutes reduced lead concentrations below 15 μg/L. However, 2% of households experienced an increase in lead concentrations with flushing suggesting that there may be other components within the well and plumbing system that release lead and/or particulate lead and may have been mobilized. To develop effective remediation and prevention additional work must be done to increase our understanding of the mechanisms of lead release in well systems. Brass fittings and components within the well might be the source of soluble or particulate lead.

Pieper, Kelsey J.; Krometis, Leigh-Anne H. ; Gallagher Daniel L; Berham, Brian L.; and Edwards, Marc; Incidence of waterborne lead in private drinking water systems in Virginia; Journal of Water and Health; 13.3 2015. Pages 897-907.

Limitations of Reverse Osmosis for Home Use

Before you buy a treatment system, you need to know the actual characteristics of your water. The test will identify the bacteria and level of minerals that are present. Proper interpretation of the test results will help determine whether treatment is needed and what type of system or systems to consider. The intended use of the water (drinking only, drinking and cooking, laundry, or all household uses) is essential to determine the what treatment is needed and the type of system to select. There is no single “best” treatment for home use, only treatment types appropriate for certain problems. The water treatment the industry has expanded to marketing treatment systems designed treat (or at least sold to treat ) contaminants that may pose a health hazards. Unfortunately, the industry is inconsistent in the skill and knowledge of the companies and their employees and many of the systems installed are inappropriate, unnecessary or have side effects that create other problems. The free in-home water testing provided by water treatment companies is very limited in scope. The only things that they can test for in the in-home tests are hardness, pH, iron and sulfur. In addition, the sensitivity and accuracy of the tests can be limited. Analysis for organics and bacterial contaminants must be performed in a certified laboratory.
Reverse osmosis systems can be used to reduce the levels of total dissolved solids and suspended matter in drinking water. The principal uses of reverse osmosis in are for the reduction of high levels of nitrate, lead, mercury, arsenic, cadmium, sulfate, sodium and total dissolved solids. Removal effectiveness depends on the contaminant and its concentration, the membrane selected, the water pressure and proper installation. Proper selection of the membrane and pressure is essential when selecting a reverse osmosis system. The membrane must be selected based on complete water analysis otherwise the entire system might be useless. In addition, reverse osmosis systems require regular maintenance and monitoring to continue to function properly over an extended period of time. Reverse osmosis has been shown to remove 83%-92% of nitrates from drinking water in both field and laboratory test. This is probably the most appropriate use of reverse osmosis systems.
I am not a fan of these systems in many applications. They are often sold as (very expensive) accessory item to solve the taste and sodium problem created when a whole house water softener is installed or for feared problems without proper testing. Reverse osmosis systems use a lot of water. They recover only 5 to 15 percent of the water entering the system. The remainder is discharged as waste water. Because waste water carries with it the rejected contaminants, methods to re-cover this water are not practical for household systems. Waste water is typically connected to the house drains and will add to the load on the household septic system. 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.
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. In addition, because contaminants are removed by forcing water through a membrane, the membrane requires regular maintenance and cleaning. Reverse osmosis systems are normally used to treat only drinking and cooking water supplies and are often installed under the kitchen sink and requires a permanent connection to an existing water pipe. The filter water is dispensed through the existing sink faucet or a separate tap. Reverse osmosis systems are never not appropriate for treating water supplies that are contaminated by coliform bacteria (neither nuisance nor fecal) because they do not remove bacteria.
Reverse osmosis units on the market range in cost from $300 to $3000 and vary in quality and effectiveness. Homes on well water need to purchase low pressure units which are slightly more expensive than the systems designed for municipal water. 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. 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 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.

There is Coliform in my Well- What to Do?

1. Retest using proper sampling procedure and verify that E coli is tested for.
2. If the sample still tests positive for total coliform then treat the system with chlorine
3. Retest the water after the chlorine has left the system in about 10 days to two weeks (make sure that the water tests negative for chlorine).
4. If your well water tests positive for total coliform then carefully check the well and water system for points of contamination.

Many instances of total coliform contamination are introduced in the water system and do not originate in the water supply. Washington State is currently investigation the percentage of problems are a result of ground water contamination.

Coliform bacteria are commonly found in soil, on vegetation, and in surface water. They 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. Coliform bacteria will not likely cause illness. However, because coliform bacteria are most commonly associated with sewage or surface waters, the presence of coliform bacteria in drinking water indicates that other disease-causing organisms (pathogens) may be present in the water system. There are three different groups of coliform bacteria; total coliform, fecal coliform and Escherichia coli (E. coli) each has a different level of risk. Total coliform serves as a proxy for fecal coliform and E. coli bacteria. Coliform bacteria do not occur naturally in most aquifers. Fractured or creviced bedrock aquifers that are close to the surface are the exception and testing for e. coli and fecal coliform and nitrogen will help differentiate the naturally occurring coliform from contamination that might impact your health.

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. Be concerned but do not panic if coliform bacteria are detected. Before treating, repairing, or replacing the well, it is wise to resample immediately if a positive sample is collected making sure to use proper testing procedures. If you receive a second positive sample for total coli forms, or if the initial sample is positive for fecal coliform, do not consume the water. 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.

The different bacterial tests are total coliform, fecal coliform, and E. Coli. The most basic test for bacterial contamination of a water supply is the test for total coliform bacteria. Total coliform counts give a general indication of the sanitary condition of a water supply. Total coliform includes bacteria that are found in the soil, in water that has been influenced by surface water, and in human or animal waste. Fecal coliform is the group of the total coliform that is considered to be present specifically in the gut and feces of warm-blooded animals. Because the origins of fecal coliform are more specific than the origins of the more general total coliform group of bacteria, fecal coliform are considered a more accurate indication of animal or human waste than the total Coliform. E. coli is the major species in the fecal coliform group. Of the general groups of bacteria that comprise the total Coliform, only E. coli is not found growing and reproducing in the environment. Consequently, E. coli is considered to be the species of coliform bacteria that is the best indicator of fecal pollution and the possible presence of pathogens.

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 sewage, 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. In an existing well system that formerly was bacteria free look for defects. These include: openings at the top of the well; old, rusty, or damaged well casing; unprotected suction line; buried wellhead; and, close proximity of a well to septic tanks, drain fields, sewers, kitchen sinks, drains, privies, barnyards, animal feedlots, abandoned wells, and surface water.

After a confirmed positive total coliform test, check following things to look for as a source of contamination introduction. Any defects in the system should be repaired, the system treated with chlorine and then retested after 10 days to two weeks. Items to look for are:

1. 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.
2. 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.
3. 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.
4. Well flooding - a common problem for wellheads located below the ground in frost pits that frequently flood during wet weather.

Since bacterial contamination cannot be detected by taste, smell, or sight, all drinking water wells should be tested at least annually for Coliform bacteria. Most state’s well construction code requires all new, repaired, or reconditioned wells to be disinfected with chlorine to kill bacteria that may have been introduced during construction. Testing is required initially to demonstrate that the water is free of Coliform bacteria before the well is put into service. A Coliform bacteria test is also recommended immediately if:

1. A sudden change occurs in your water’s taste, appearance, or odor.
   The water turns cloudy after rainfall or the top of the well was flooded.
2. You suspect a contamination source (e.g., septic system or barnyard) is within 50 feet of your well.
3. Family members are experiencing unexplained flu-like symptoms.

Before implementing one of the solutions listed below, be sure to inspect the well for defects, check the grouting, casing, and clean the water delivery system and filter of slime and flush the system fully. Then retest. If the system passes let a few weeks go by and retest again. If repairing and cleaning the system does not solve the problem then one of the long-term solutions will have to be implemented.

Long-Term Options for Dealing with Bacterial Contamination of a Well

1. Connecting to the regional public water system, if possible
2. Constructing a new well (it is best to determine the source of contamination before a new well is installed)
3. Installing continuous disinfection equipment
4. Using bottled water for drinking and food preparation