Now is a good time for the nearly 1 million Wisconsin households that get their drinking water from private wells to test the water’s safety, and a new video shows people how to do that to get accurate test results.
The video showing how to collect a water sample, lists of certified labs that can test the water, and information on keeping your private water supplies safe is available on the private well testing page of the Department of Natural Resources Web site.
“Most private wells provide safe drinking water, but we tend to see an increase in well contamination problems after spring thaw,” says Mark Putra, who leads the private water section for the Department of Natural Resources drinking water and groundwater program.
Private wells can become contaminated with bacteria that is not filtered out as the water soaks into the ground, moving through shallow fractured bedrock, quarries, sinkholes, inadequately grouted wells or cracks in the well casing. Insects or small rodents can also carry bacteria into wells with inadequate caps or seals.
The DNR recommends that people test their private wells at least once a year for bacterial contamination and any time they notice a change in how their water looks, tastes or smells.
Certified labs can easily test water for coliform bacteria, an indicator that a disease-causing contaminant might be present, and e-coli, a bacteria that can cause human illness. Homeowners will need to collect a water sample from a faucet near the well, following the instructions and using the sample bottle provided by the laboratory.
Too often, people get an inaccurate result because they fail to disinfect the faucet before collecting a water sample. Without proper disinfection, the sample may reflect bacteria present on the faucet and not in the water. Or they may touch the inside or the cap of the sampling bottle, potentially contaminating the sample with bacteria present on their hands.
Tests for other contaminants may be warranted
Spring is also a good time to test well water for other contaminants if you know your area has a problem with particular ones because of the surrounding land uses or the bedrock formations holding the groundwater your well taps.
Owners of existing homes with private wells can use the groundwater Web site to understand what contaminants they may want to have their water tested for for a variety of reasons.
The groundwater Web site wi.water.usgs.gov/gwcomp incorporates selected groundwater data from 16 federal, state and local agencies and provides maps and other information about groundwater in each of Wisconsin's 72 counties. The site was developed through a partnership of state and federal agencies and the UW-System and funded by the DNR and the University of Wisconsin system.
FOR MORE INFORMATION CONTACT: Mark Putra (608) 267-7649 or your local drinking water specialist