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Hurricane recovery: Private well owners should test well water after flooding

By Andrea Albertin, UF/IFAS Water Resources Agent, Northwest District

As Hurricane Michael heads towards the Florida Panhandle and Big Bend area, it is important for private well users to ensure the safety of their drinking water.

If wells are damaged or flooded, residents should assume their water is contaminated by bacteria. The well water should not be used for drinking, cooking, making ice, brushing teeth or even bathing until it is tested by a certified laboratory for coliform bacteria and E. coli.

Residents should use bottled, boiled or treated water until their well water has been tested and deemed safe.

  • Boiling: To make water safe for drinking, cooking or washing, bring it to a rolling boil for at least one minute to kill organisms and then allow it to cool.
  • Disinfecting with bleach: If boiling isn’t possible, add 1/8th teaspoon or about 8 drops of unscented household bleach per gallon of water (4 to 6% active ingredient). Stir well and let stand for 30 minutes. If the water is cloudy after 30 minutes, repeat the procedure once.
  • Keep treated or boiled water in a closed container to prevent contamination

Use bottled water for mixing infant formula.

Where can you have your well water tested?

Most county health departments accept water samples for testing. Contact your local health department for information about what to have your water tested for (they may recommend more than just bacteria), and how to collect and submit the sample.

Contact information for county health departments can be found on this site:

You can also submit samples to a certified commercial lab near you. Contact information for commercial laboratories that are certified by the Florida Department of Health are found here: This site also includes county health department labs as well as university labs and others. You can search by county.

What should you do if your well water sample tests positive for bacteria?

The Florida Department of Health recommends well disinfection if water samples test positive for total coliform bacteria or for both total coliform and E. coli, a type of fecal coliform bacteria.

You can hire a local licensed well operator to disinfect your well, or if you feel comfortable, you can shock chlorinate the well yourself. Texas A&M’s AgriLife Extension Service provides detailed instructions on how to shock chlorinate your well in both English: and Spanish:

After well disinfection, you need to have your well water re-tested to make sure it is safe to use. If it tests positive again for Total coliform bacteria or both Total coliform and E. coli call a licensed well operator to have the well inspected to get to the root of the problem.

Well pump and electrical system care

If the pump and/or electrical system have been underwater and are not designed to be used underwater, do not turn on the pump. There is a potential for electrical shock or damage to the well or pump. Stay away from the well pump while flooded to avoid electric shock.

Once the floodwaters have receded and the pump and electrical system have dried, a qualified electrician, well operator/driller or pump installer should check the wiring system and other well components.

Remember: You should have your well water tested at any time when:

  • A flood occurred and your well was affected
  • The color, taste or odor of your well water changes or if you suspect that someone became sick after drinking your well water.
  • A new well is drilled or if you have had maintenance done on your existing well

The Florida Department of Health (FDOH) maintains an excellent website with many resources for private well users which includes information on potential contaminants and how to maintain your well to ensure the quality of your well water.