Last week's flooding plus a new onslaught of rain puts home owners' wells at risk of contamination.
A good part of Ravalli County was plagued with flooding. Water seeped onto roads, and into garages and houses.
It's important that well heads remain as dry as possible.
Ravalli County sanitarian Dan Hooten drove through Hamilton's west side Monday, surveying areas that had been flooded. He said standing water on or near a well head can seep into the well and aquifer.
The Bitterroot may be especially vulnerable.
"We have thousands of wells," said Hooten, "except for the incorporated cities that have water systems, everyone has a well that feeds their home."
Hooten said spigots should be placed at least 20 feet away from well heads to reduce possible contamination.
If your well is in a low lying area, be aware of standing water.
Sanitarian John Palacio said, "You want to prevent water from the casing. You want to make sure the casing is tight and you don't have cracks in it. Build up an incline to prevent water from going down."
If you are concerned about your water quality the sanitarians suggest you test your well. The department provides test kits for free, although you need to pay for lab analysis.