Spring snowmelt and rain can contaminate private wells

MADISON -- As spring approaches, warming temperatures, snow melt, residual frozen ground and rain events all create conditions that can affect private wells and drinking water.

"Now is the time of year for well owners to watch for signs of flooding and to notice any change in the color, smell or taste of their drinking water," said Liesa Lehmann, private water section chief for the Department of Natural Resources.

DNR drinking water staff advises well owners who observe flooding or changes in their water to assume their wells are contaminated and to take the following steps:

• Stop drinking well water and find an alternate source of safe water to drink.
• Make sure the well is properly disinfected.
• Before resuming consumption of the water, sample the well after pumping and disinfection to assure the water is safe.

Flood waters and runoff contain bacteria and other contaminants that can affect water supplies and cause water-borne illness. Wells located in pits, basements and low-lying areas are especially susceptible to contamination. Even without obvious signs of flooding, a well can become contaminated.

"Disinfection and sampling is best done by a licensed well driller or pump installer," said Lehmann.

Any water supply system that has been submerged by flood waters should be pumped out once the floodwater recedes, then thoroughly disinfected and tested to determine that the water is safe.

Well owners are encouraged to test their wells annually for bacteria and nitrates, to check for problems and ensure the water is safe to drink. More information on bacteriological contamination of drinking water wells, along with lists of licensed well drillers, pump installers and labs certified to analyze water samples is available by searching for keyword " wells" on the DNR website.

For individuals who receive their drinking water from a public water supply, these systems are designed and operated to keep out contaminants. Anyone with concerns about the safety of their community's drinking water, contact your public water supplier.