Guides

Your well after a flood

The CDC lists flooding near your well as a reason to test your well water.¹ If floodwater reached your well, don't drink the water until it's tested. Here are the steps, in order.

1. 1. Do not drink the well water yet

   If floodwater reached your well, or you think it may have, do not drink the water. Drink and cook with bottled water or water from another safe source. If you have no other water, boil your well water before you drink it.^{2, 3}

2. 2. Know why a flood matters

   Runoff from rain and floods can wash germs into a well or let them seep underground. Germs in drinking water can cause stomach illness and infections.^{4, 5}

3. 3. Have the well disinfected

   After a flood, the CDC says a well or pump contractor should disinfect the well, for safety reasons.⁶

4. 4. Wait, then test the water

   Wait at least 7 to 10 days after the well is disinfected, so the chlorine is flushed out, then test the water. Use a state-certified laboratory. Test again to make sure the treatment worked before you drink the water.^{7, 8, 9}

5. 5. Ask for local help

   Your local health or environmental department can help you read the results and decide what to do next.¹⁰

Sources

1. 1. CDC, Guidelines for Testing Well Water: “You should also have your well water tested if: You are notified that there are problems with well water in your area, There are problems near your well, such as flooding, land disturbances, or nearby waste disposal sites, You replace or repair any part of your well system, You notice a change in your water's taste, color, or smell, You or someone you live with becomes pregnant, A child starts living with you” (checked 2026-10-19)
2. 2. CDC, Guidelines for Treating Well Water: “If your well is contaminated with harmful germs or chemicals, or you suspect it is, do not drink your well water. Instead, drink and use bottled water or water from another safe source.” (checked 2026-10-19)
3. 3. CDC, Guidelines for Treating Well Water: “If you cannot use bottled water or another safe source of water while you are having your well water treated, boil your well water before drinking it.” (checked 2026-10-19)
4. 4. EPA, Potential Well Water Contaminants and Their Impacts: “Water run-off from rainfall or snow-melt can contaminate private wells by washing microorganisms into the well system or seeping underground.” (checked 2026-10-19)
5. 5. EPA, Potential Well Water Contaminants and Their Impacts: “People that consume drinking water containing microorganisms can experience gastrointestinal illnesses and infections.” (checked 2026-10-19)
6. 6. CDC, How to Disinfect Wells After an Emergency: “Wells should be disinfected by a well or pump contractor, due to safety concerns.” (checked 2026-10-19)
7. 7. CDC, How to Disinfect Wells After an Emergency: “Wait at least 7 to 10 days to test the water after disinfection to ensure that the chlorine has been thoroughly flushed” (checked 2026-10-19)
8. 8. CDC, Guidelines for Testing Well Water: “Use a state-certified laboratory to test your water.” (checked 2026-10-19)
9. 9. CDC, Guidelines for Treating Well Water: “Then, test the water to make sure the treatment worked before drinking or using it.” (checked 2026-10-19)
10. 10. CDC, Guidelines for Testing Well Water: “Contact your local health or environmental department. They can help you understand the test results and what to do next ...” (checked 2026-10-19)