Test a Well for Chemical and Bacterial Contamination Before You Buy a Home

Picture from Moen Website

If your home or a home that you are considering buying has a drinking water well that is contaminated, it could significantly impact your health and the value of the property. Never buy a home with a contaminated or failing well. Testing a well is a very important part of a real estate transaction, and only by fully testing the water can you be certain that it is not contaminated. When buying a home with private water well you need to understand at a minimum the basics about groundwater, the age of the well, the local geology, water quality, and water quantity.  Most single family homes transactions only test a well for coliform bacteria contamination, nothing more. Total coliform bacteria is always present in manure and sewage, but is also present in soil and vegetation and surface water. The presence of coliform bacteria may indicate that the well has been impacted by a nearby septic system or manure composting; it can also mean that surface water is getting into the well either directly through a failing casing or grouting or improper construction or well cap or by other means. Absence of coliform bacteria only means that water is not contaminated by septic and surface runoff, but the water might be contaminated from other sources.

In a world not subject to chemical contamination of the aquifer (from pesticides, herbicides, solvents and fuels present in stormwater runoff) or high natural concentrations of arsenic or metals, a coliform bacteria test is a fairly decent test to determine potential outside impact to a well and sound construction. If you do not test for it you will not find it. Water contains a variety of impurities beyond the simply H2O molecules. Not all of the impurities and contaminants are bad, some make water taste good.  The US EPA’s Safe Drinking Water Act does not protect private wells; however, the limits for the primary and secondary contaminants are a good standard to compare water to when testing a well.

Due to its protected location underground, most groundwater is naturally clean and free from pollution. Typically, the deeper the well the less likely is it to be contaminated from nearby industrial operations. However there are a number of threats to drinking water: improperly disposed of chemicals; animal wastes; pesticides; human wastes; wastes injected deep underground; and naturally-occurring substances can all contaminate drinking water and make it unsuitable for drinking or make the water unpleasant to drink. It is important to know the land history of a site. Homes built on former disposal sites- farm dumps, landfills or former military operations are particularly susceptible to contamination. Former agricultural properties should be tested for pesticides, fuels and solvents because farmers often have fuel tanks and repaired farm equipment with solvent that were improperly disposed of over the years.

The nightmare scenario is what happened in Sterling, Virginia as documented by Rosemary Stephen in her article “Trichloroethylene(TCE) Water Contamination.”  The short story is that for twenty or thirty years homeowners in a community in Sterling, Virginia (a community in Loudoun County) were drinking water contaminated with TCE and its degradation products. The homes had been built on and old landfill and back in 1988 the Loudoun County Department of Health and the EPA had found traces of TCE, its degradation products and pesticides in three residential wells, but because the contamination was below the regulated maximum contaminant level (MCL) no further investigation was performed. Apparently, the oddity of finding a solvent in groundwater in a residential community did not immediately prompt further investigation. The water was within safe limits and thus was fine.

However, the water in the neighborhood was not fine. In 2005, 68 more wells (in the community) were tested by the Health Department. “Forty-five wells tested positive for TCE; 17 of these wells contained concentration of TCE above the maximum contaminant level (MCL) of 5 micrograms per liter (mcg/L) while 28 wells contained TCE, but below the MCL.”  The site was declared a CERCLA (Superfund) site in 2008. Between 1988 and 2005 no testing was done on the individual homeowner wells. The water was consumed by the young and old and the homes were bought and sold. If your home had been declared within a Superfund site, it is very likely that the value of the home would be impacted.

To be prudent and smart you need to test the well for likely sources of contamination. When I was working as an Environmental Engineer, the biggest challenge was to adequately research the history of a property and then test the soil and groundwater for contamination in the areas most likely to be contaminated. Testing is very expensive, so it is virtually impossible to fully test soil and groundwater.  In buying a single family home, you do not have any of this information or resources available to you. Neighbors can be useful or just have no understanding of environmental and groundwater issues and tell you nonsense they’ve heard. If someone asked me about groundwater in my community or my opinion about any specific well, I would tell them, but they would not know my level of expertise. While there are some good historical records available for industrial and commercial properties there is very little information available for residential properties. The department of health often has some useful information about water quality in the county and septic systems, but rarely has any water analysis data available.  Chemical analysis can be very expensive, and there is no requirement that private wells be tested at all and most health departments do not have budgets for testing water quality.  

However there are screening packages available from National Testing Laboratories that could serve to screen water wells for all the primary and secondary contaminants before you purchase a home. Their WaterCheck with pesticides package 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.  WaterCheck with the pesticide option costs $217. You will also have to pay overnight shipping cost ($40-$70) to return the package.   

In order to complete the analysis before you are committed to purchase a home, you will need to purchase the WaterCheck package before you put an offer on a home. Have the package ready, read the instructions and include in the purchase offer a water analysis clause that specifies that the contingency period must be long enough to allow for the analysis and the water quality must be acceptable to you. At least that is what I used; I did not specify that the water quality must be within all primary MCLs and within recommended secondary contaminant levels because some of the secondary contaminants are common minerals in groundwater and are regionally high. Make sure that you test the water before any treatment equipment that the home may have, activated carbon filters and distillation units can remove some solvent and hydrocarbons from the water. If any water treatment systems exist in a home you want to test the water before treatment and after treatment so that you understand what the water is being treated for and if the treatment is effective.  

My water tested "hard," but I was fine with that. The levels of all other secondary contaminants were within recommended limits. All primary contaminants were below the MCL and all hydrocarbons and solvents were not detected at any level. There is no good explanation for the presence of volatile organic chemicals in a drinking water well. Even extremely low levels may indicate a significant problem.  Also, be aware that a common nuisance contaminant in this part of the county is iron bacteria. Iron Bacteria can cause both unpleasant odors and taste to your water as well as cause clog screens and ultimately foul a pump. There is no EPA approved analysis for these bacteria, but there are assay tests. An easy way to see if there are iron bacteria in a home is to stick your hand in the toilet tank and feel the flapper. Iron bacteria leave slime on the flapper and you can feel it with your fingers. Of course if the tank is brown or orange there is likely an iron problem or the iron bacteria has gotten completely out of hand. Once iron bacteria are in a well, it is really hard to get rid of, but fairly easy to control with annual disinfection.  When I bought a home I wanted the water to be acceptable as it was. Water systems are dynamic and do change, and over time I discovered that slime was appearing on my toilet flappers and have had to address the iron bacteria and the annoyance of the annual treatment (which causes all the manganese and iron particles that treatment freed from the well to remain in the water supply until the well fully clears).

To ensure that you will have adequate time to test water quality before releasing all contingencies, you will need to check with the laboratory for turnaround time to make sure your contingency period is long enough. Do not let a realtor pressure you to skip this test because it could take a couple of weeks. When I bought my home in 2007 I could only negotiate a 10 day contingency period and had to pay a huge premium to have the well analysis done on a rush basis. Remember the mortgage takes longer so just include the time- fight for it; this is the most money you will ever spend. While you are at it, check when the last time the septic tank was pumped and the septic system inspected.