If you have a private well water supply after heavy rains or flooding is a good time to inspect your well and get your drinking water tested at a certified laboratory. Proper well construction can help keep outside water, debris, and rodents from getting into your drinking water source, but sometimes small issues can go unnoticed.
Drinking water contaminants are usually absorbed by the soil before they enter a well but sometimes if a well isn’t sealed or constructed correctly they can enter the system. In particular, severe weather and flooding can make these issues worse.
Private wells should be tested annually for coliform bacteria. This bacteria in itself is harmless but is an indicator that some other potentially dangerous bacteria may also be in your water such as E. Coli. If any foreign material such as rodents or animal feces ended up in your well, a coliform bacteria test can tell you whether or not you need to investigate further.
To take a water sample, work with a certified water testing lab near you. They will provide instructions on how and when to test your water. Make sure to follow handling and sanitizing instructions since there can be false-positive results if you don't sanitize your faucet well enough before sampling.
Minnesota has had an established well code since 1974, making well construction standardized.
If applicable to your area some wells have a gas vent from the cap with a mesh screen.
When inspecting your well make sure all these features are being met. Some things to look for are:
Any one of these can be an opportunity for different contaminants to enter your well. If you have something that needs to be fixed you can contact a licensed well driller to get an inspection and estimate of costs.