If flooding occurs around your water well, your drinking water may have become contaminated. When flood waters rise over the top of the well, contaminants can enter through the well cap or vent and increase the risk of illness. The well can act as a drain as flood water cascades down the casing into the aquifer.
What is the problem?
Flood water contains bacteria and viruses from soil, organic debris, and sewage systems along with fertilizers, pesticides, and other chemical contaminants. Shallow wells and old, poorly constructed wells (e.g., dug wells) are vulnerable to water quality changes when flood waters deposit contaminant close to the well.
What about old wells and well pits?
Older wells located in below grade pits are vulnerable to contamination from flooding, even if flooding
at the ground surface did not occur. Well pits are unsanitary and are prone to flooding after heavy
spring rains or rapid snowmelt occur and surface water or the water level within the surrounding soil
gathers within the pit.
What do I do if my well becomes flooded?
If your well has been flooded, you should immediately refrain from drinking the water and the
following steps should be taken:
1. Once the flooding recedes, begin flushing the water system. Hook a hose up to an outside faucet or a faucet near the water storage tank and flush the water for at least two hours after the water clears up. If a large volume of flood water entered the well, several hours of pumping may be needed. Once the water is clear at the storage tank, flush the home distribution piping.
2. Contact a Michigan registered water well drilling contractor and request that your water system be disinfected.
3. After flushing the chlorine from the system, collect a water sample and submit it to a certified laboratory for coliform bacteria analysis. You can contact your local health department office for water sample bottles.
4. Contact your local health department office for further assistance, if needed.