What Should be Included in a Drinking Water Test

July 6, 2021

This article originally appeared in WQP May 2020 issue as "Peace of Mind"

About the author:

Marianne Metzger is laboratory sales executive for ResinTech Inc. Metzger can be reached at [email protected]

In the water treatment market, at some point, you are likely to have a client ask to have their water tested. The big question is: “Tested for what?” Depending on the client, the answer could be drastically different. For example, a homeowner with a private well might have different water quality priorities than a factory trying to treat a waste stream. In either case you can be prepared to make recommendations by doing some homework and listening to your clients’ needs.

The first step in unraveling this puzzle is to determine the source of water to be tested. Is that water a private well, municipal tap water or is the water being used in a process that must be treated before it can be released into the sewer systems? The source of the water can indicate what contaminants may be present. 

Testing From Community Water Supplies

Let us tackle waste water stream as it is probably the most straight forward. When a business needs to treat water used in a process before it can be released into the sewer system, this means that the state has already determined that there is something in the water that needs to be treated and will issue a permit for discharging. In these cases, the business is required to perform tests and submit them to the state proving they are not discharging water that contains contaminants in excess of the limits established by the state. When treating water in these instances, there is typically already testing data unless it is a new permit. Additional testing may be necessary to help determine treatment needs. For example, when considering an ion exchange solution, it may be necessary to determine what competing ions may be present and at what levels to ensure equipment is sized and maintained properly.

Next, there are customers that are on community water supplies. Whether it is a business or a residential application, there should be some testing data already available. Every public water supply is required to publish a Consumer Confidence Report (CCR), which can provide some valuable insight on the source of water and quality. Community water supplies are required to provide their customers a CCR annually, which at a minimum includes: the source of water; definitions describing Maximum Contaminant Levels (MCL); Maximum Contaminant Level Goals (MCLG) variance and exemptions; reporting of any detected regulated contaminant; information on unregulated contaminants, such as Cryptosporidium and radon; and a statement that more information is available by calling the Safe Drinking Water hotline. 

It is important to keep in mind that the testing data reported is from the previous year of testing and reflects the water quality as it leaves the treatment plant in most cases. This means that the quality can change as the water travels through the distribution system, usually due to disinfectants reactions taking place and picking up contaminants from the distribution systems itself, such as lead and copper. 

Testing Residential Private Well Water Quality

Residential private wells have the most unknown factors in terms of water quality because many homeowners will do minimal testing, if at all. At a minimum, the U.S. EPA recommends those on private wells test for Coliform and E.coli bacteria and nitrates each year. There are numerous possibilities for contaminants due to a variety of factors. 

First, there are naturally occurring contaminants, such as metals, minerals and radiological contaminants, including radon and uranium. These contaminants come from the geological formations that the water travels through and can vary based on how much water is in the aquifer. Drought conditions can concentrate contaminants while lots of water may dilute or possibly cause additional contamination due to reaching different geologic formation. When testing in private wells, it is a good idea to test at different times of year to get a better idea of what the worst-case scenario is for these naturally occurring contaminants. 

Other contaminants would have to be introduced into the groundwater, and this depends on a number of factors. The first factor is the depth of the well or aquifer — the deeper the well the longer contaminants have to travel. Shallower wells are contaminated much quicker than deeper wells, which was highlighted in a recent study by the Environmental Working Group on per- and polyfluoroalkyl substances (PFAS) where deeper wells had little to no contamination. Another important factor is the composition of the soils in the area. For example, sandy soils allow contaminants to quickly move through while layers of clay can slow down and stop contaminants. The amount of rain also can play into this because rain carries contaminants quicker through the ground. Finally, it depends how soluble the contaminant is in water. The higher the solubility the more likely it will end up in groundwater. Contaminants that have a lower solubility can get stuck to soil particles and not move with rainwater into the aquifer. 

When determining what should be tested for in private wells, geology in the area should be considered. The U.S. Geological Survey, your local health department and county extension offices are great resources on what naturally occurring contaminants may be present in your area. 

It is also important to see what sources of contaminants are nearby. For example, are there any underground storage tanks or gas stations nearby, dry cleaners or landfills? These could potentially contribute volatile organic contaminants into the groundwater. If the well has not had an extensive test done, it may be a good idea to do a more comprehensive test to provide a baseline and rule out certain contaminants in future testing. There are several somewhat inexpensive testing options available that can give homeowners and water treatment professionals valuable information on the water quality to ensure the water is treated properly. Numerous contaminants do not make themselves known in obvious ways — such as taste, odor or discoloration — so the only way to uncover them is to perform a test.

Finally, and most importantly, talk with your customers about their concerns with water quality and make sure to take those concerns into account when talking about available testing options. While most homeowners will let you know right away about the problems they can see and taste in water, also consider they may have specific health-related concerns that you want to ensure you address. Medical conditions present additional concerns and water treatment can offer some peace of mind. 

About the Author

Marianne Metzger

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