Iowans with private water wells could be at risk of having their drinking-water supply contaminated by flooding. Older wells are larger and often not sealed from surface contamination, according to public-health engineer Michael Magnant. Anytime surface water runs into a well, expect some bacteria. The type depends on where that water came from, but we would almost certainly find coliform bacteria there. Manhunt says you can contact a county office to find out how to take a water sample and get it tested. But he says, if floodwaters swamped a drinking water well, you should assume it’s been tainted. He says to go ahead and flush out the well and your pipes. Run water till it’s clear, and floodwater’s flushed out. Magnant says the next step for cleaning a contaminated well is to kill remaining germs.Do what’s called “shock chlorination,” adding quite a bit of chlorine. Directions for that do-it-yourself disinfecting are available free from county health departments. Coliform bacteria and other kinds of disease-causing germs can be washed into the well by floodwaters.
