Your well after a flood

If floodwater reached your well, EPA says don't turn on the pump and don't drink or wash with the water until the well is checked, disinfected, and tested.

First, don't

• Don't turn on the pump. EPA: "There is danger of electrical shock and damage to your well or pump."
• Don't drink or wash with the water. "People drinking or washing with water from a private well that has been flooded will risk getting sick."

Check the well

• "Wells that are more than 10 years old or less than 50 feet deep are likely to be contaminated, even if there is no apparent damage."
• Have the wiring checked "by a qualified electrician, well contractor, or pump contractor" before you turn anything on.
• "Drilled, driven or bored wells are best disinfected by a well or pump contractor."

Disinfect it (EPA's steps)

1. If the water is muddy, run an outside hose until it runs clear.
2. Get one gallon of unscented household bleach, rubber gloves, eye protection, and a funnel.
3. Pour the bleach into the well casing.
4. Run an outside hose into the casing until you smell chlorine at the hose.
5. Open every cold faucet, inside and out, until each smells of chlorine, then shut them. Put any treatment system on bypass first.
6. Wait 6 to 24 hours. Don't drink, cook, bathe, or wash with the water during that time.
7. Run an outside hose into a safe spot, away from plants, streams, and the septic tank, until the chlorine smell is gone.

Source: EPA, What to Do After the Flood.

Then test it

"Have your water tested for bacteria 7 to 10 days after disinfection." EPA also warns "your well may not be a safe source of water for many months after the flood," so test again later.

• Find a well test near you (your health department or state lab)
• By mail: Tap Score's coliform and E. coli test, $99 (Tap Score, price checked October 2, 2026)

We earn a small commission on Tap Score sales, which helps more people find low-cost water testing.

Your state's flood guidance

• Alabama: Alabama Cooperative Extension System, Flooded Wells: Shock Chlorination
• Arizona: Arizona Department of Health Services, Well Water Quality Emergencies
• Connecticut: Connecticut DPH, Flooding: Information for Homeowners About Private Wells, Sewage and Clean-Up
• Delaware: Delaware DNREC, Protect Your Well (Flood Prone Areas)
• Florida: UF/IFAS Extension, Private Wells 101: Bacterial Contamination and Shock Chlorination
• Georgia: UGA Extension, Ensuring Safe Private Well Water for Household Use After a Flood
• Illinois: University of Illinois Extension, Have You Inspected Your Well?
• Maryland: University of Maryland Extension, What to Do After the Flood (Wells)
• Massachusetts: Massachusetts DEP, Recommendations for Private Wells Inundated by Flooding
• Minnesota: University of Minnesota Extension, Test Your Well Water After Flooding
• Missouri: Missouri Department of Health and Senior Services, Well Water Test Kit Information and Services
• Montana: Montana DEQ, Flooding Resources (Private Wells)
• Nebraska: Nebraska Extension, Private Well Protection from Flood Waters and Management After a Flooding Event
• New York: New York State Department of Health, Restoring Your Private Well
• North Dakota: North Dakota DEQ, Proper Well Disinfection (Flood Information)
• Rhode Island: Rhode Island Department of Health, Private Wells (Keep Your Well Water Safe in an Emergency)
• Tennessee: UT Institute of Agriculture Extension, Flood Related Resources (Private Well and Septic Guidance)
• Vermont: Vermont Department of Health, After a Flood: Private Drinking Water Guidance
• Virginia: Virginia Cooperative Extension, Safeguarding Your Well and Septic System Against Flooding Hazards
• Washington: Washington State Department of Health, Floods: Be Prepared, Be Safe
• Wisconsin: Wisconsin DNR, Recommendations for Private Wells Inundated by Flooding

Help paying for well repairs · How often to test a well

EPA guidance checked October 2, 2026. Follow your state or local health department if its advice differs.