May 8, 2012
MADISON - Flooding in some parts of northeastern Wisconsin is adding urgency to water officials' annual reminder that now is a good time for private well owners to test their water to make sure it's safe to drink.
"We encourage private well owners to test their well for bacteria at least once a year, regardless of where you live, and it's particularly important for well owners in flooded areas to have their wells tested," says Steve Ales, Department of Natural Resources section chief for private water. "If your well is surrounded or overtopped by floodwaters, it shouldn't be used until after you have it tested and the water is found to be safe to drink."
The DNR recommends that well owners sample their wells once a year for bacteria and any time they notice a change in taste, odor or color. When flooding occurs, well owners should suspect that their drinking water is contaminated by floodwaters if the well casing becomes inundated; if there's a change in taste, color or sediment; or if the well does not have a deep casing and you are near areas that have been flooded. Wells located in pits and basements are especially susceptible to contamination.
More information on wells in flooded area and testing can be found by searching for coping with flooding on the DNR website.
Wisconsin has about 1 million private wells, and about 14,000 new wells are drilled every year. Private well owners are responsible for testing their wells to make sure the water is safe to drink.
Most private wells provide safe drinking water, but there tends to be an increase in well contamination problems after spring thaw when melting snow soaks into the ground; those problems are exacerbated when there's flooding, Ales says.
Some wells may become contaminated with bacteria that are not filtered out as the water soaks into the ground. Surviving bacteria can finds their way into the groundwater by 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,
Well owners may want to test for other contaminants, like nitrate, arsenic or agricultural chemicals depending on the surrounding land use practices in the area, Ales says.
FOR MORE INFORMATION CONTACT: Steve Ales (608) 267-7649 or your local drinking water specialist