Well Potability 101
Advisory Report - September 2003
Well Potability 101
Have you ever wondered why well water analysis’ are done they way they are for Relocation properties? There is a very simple answer. In 1991 the Employee Relocation Council developed and published the “Relocation Home Inspection Guide.” This guide makes the recommendation that all private wells be tested for the presence of coliform or nitrates in the water provided by the well. In this article we’ll explain the concerns with nitrates and coliform, how the testing is completed and appropriate remediation methods if sampling analysis reveals nitrates or coliform contamination.
Prior to discussing the well water testing procedures recommended by the Employee Relocation Council Home Inspection Guide, it is important to note that recently many states and local municipalities have passed legislation requiring that a more extensive water test be performed. In those instances it is imperative that the water test adheres to the additional guidelines.
When a standard test is performed per ERC guidelines, the water is tested for chlorine, in addition to testing for coliform and nitrates. Although testing for chlorine is not required by ERC, it is essential to identify because the presence of any amount of chlorine will hide the presence of bacteria. There is no naturally occurring reason for chlorine to be present in well water. Its presence indicates that a well has been “spiked” to hide bacteria or that it is being added to kill bacteria as part of a treatment program. The chlorine test is done first and if chlorine is detected, further testing is not performed, with the results being reported as “Indeterminable.”
If initial testing does not confirm the presence of chlorine, the sample is then tested for nitrates and coliform. Nitrates are a by-product of fertilizers. Ingesting high levels of Nitrates reduces oxygen content in the blood, which is a particular concern with young children. A high level of nitrate most commonly indicates that surface water is leaching into the well casing. The testing procedure for nitrates produces a numerical count of the nitrate present. Levels below 10.0 are considered safe and acceptable. If nitrate contamination is identified, it is recommended that a reverse osmosis filter be installed.
Lastly, the water sample is analyzed for the presence of coliform bacteria. This test is performed by adding a chemical to the water sample and letting it sit for 24 hours. If there is any coliform bacteria present in the water sample it will react by changing color. The test cannot be sped up and produces either a present or absent result. Coliform bacteria can produce various ill health effects. If bacteria is found the lab will run a further test to determine if it is E. coli. This bacteria strain is most commonly caused by septic contamination. Bacteria contamination can be difficult to determine. The source of the contamination could be from various sources such as a tap, the lines or even the well itself. In all cases of coliform bacteria contamination the proper remediation procedure is to have a well specialist treat the well with chlorine.
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Contributed by Jim Firnbach
Network Supervisor, GHI
U.S. Inspect, LLC