One message that’s likely to be repeated, whether you’re reviewing information here at Wellwatertalk.com or reading the EPA’s guidance on private drinking water wells, is that the owner of a private water supply, like a well, is solely responsible for the quality of the water. And it’s definitely worth repeating.
Public drinking water, like for a city or campground, may also come from groundwater, such as a well, but, that water quality is governed by the local authorities and is filtered and disinfected and held to a high quality standard to ensure it’s safe for those drinking it. In order to maintain those standards, the water may be tested multiple times a day, depending on the number of people relying on that water. Even small water systems are required to test regularly – though less often for smaller systems – because testing is the only way to know for sure that the water is safe for drinking. So, if you and your family – or you and a few neighbors – are the only people using your water source, how often should you be testing your water?
For the most part, there isn’t a “one size fits all” answer to this question. That’s because so many things can influence
water quality – beginning with geology. The USGS has identified 62 principal aquifers that provide groundwater to
Americans and has grouped them into nine regional geologies. Each has unique characteristics, including the types of natural contaminants (like arsenic, radium, manganese) and man-made contaminants (such as nitrates or pesticides) likely to be found. You can check out your region with the interactive map found here.
Land-use is another critical factor that affects water quality. Agricultural production – be it crops or livestock – accounts for roughly 51% of the U.S. land base. Fertilizers and manure can infiltrate ground water, leading to unnaturally high levels of nitrates and bacteria. Agriculture can also be tremendously draining on ground water supplies, between the water needed for irrigation and feeding livestock.
“High-volume pumping and irrigation in many areas have profoundly changed groundwater flow and quality. By moving shallow groundwater deeper, into parts of aquifers used for drinking water, irrigation and pumping have increased the vulnerability of drinking-water supplies to contamination from nitrate, pesticides, and other manmade chemicals from the land surface.” [USGS press release]
And then there’s the weather. Dry or wet, it can have a significant effect. Drought, which is currently affecting 46% of the U.S. (as of Jan 27/15), can cause the water table to drop over time and impact water quality. Or severe rain events and flooding can suddenly wash surface water into your well, introducing disease-causing microorganisms like E.coli, Cryptosporidium, or Giardia that can’t be detected by taste, odor, or appearance.
Taking all of this into consideration, here are some water testing guidelines:
If you are drilling a new well or deepening an existing well, test for the basics:
- Bacteria (total coliform and/or coli)
- pH, color, turbidity
- Check with local authorities about any heavy metals like arsenic, as well as radionuclides and radon, that may be naturally occurring in your region. Include these tests when a new well is drilled or your well is deepened, and follow regional guidance for repeat testing. For some contaminants, it may be every 10 years, while others might be every two or three years. A good resource for this information is www.water.epa.gov/drink/info/well/whereyoulive.cfm.
- Test for bacteria and nitrates at least once a year. This is the minimum. Both these contaminants are associated with agricultural run-off and septic tank leakage and can be greatly influenced by heavy rain events and localized flooding, such as during a spring thaw. If you have any reason to suspect possible bacterial contamination, re-test the water.
- Special circumstances in your household should also prompt a water test. Is someone in the house pregnant? Are your elderly parents visiting or moving in? Is anyone experiencing un-explained gastrointestinal illness (vomiting, diarrhea)? Is there a noticeable change to the color, taste, or odor of your water? All of these suggest a water test is likely needed.
Being a private well owner effectively makes you a water system operator. To repeat, the responsibility for ensuring your water is safe is on you and you alone. Regular water testing is the best way to ensure the quality of the water your family is using for cooking, drinking, and even bathing. It’s a changing world, and many of the factors affecting water quality are out of your control. It’s no longer reasonable to test your water when the well is built and then forget it. Water quality changes. Land use changes. Weather patterns change. Routine water testing is just the smart – and safe – thing to do. And even if your water test comes back okay, at some point, it’s worth repeating.