Ensuring Safe Well Water After a Flood

Ensuring Safe Well Water After a Flood

The following information is from the Nebraska Extension website, Flood.unl.edu, where you can find additional flood recovery information.

Protect Wells from Flood Water

  • Disconnect the power supply.
  • If possible, have the well vent replaced with a water-tight plug, or have the casing permanently extended above flood level.
  • Cover the top of the well with heavy-duty plastic and tightly secure it with waterproof tape (not duct tape) to keep debris and sediment out of the well, making post-flood clean-up easier.
  • Prepare to have the well tested and disinfected (if needed) after flood waters recede.
  • If cost-effective and feasible, consider disconnecting and moving expensive water system components such as the water heater and water treatment equipment.
  • Sandbag for Flood Protection (eXtension resource)
  • Water-Inflated Flood Barriers (eXtension resource)

Managing Private Drinking Water Wells After Flooding

Flood waters commonly have high levels of bacteria. after flood waters recede, have the well water tested by a certified laboratory. If the well is contaminated, disinfect the entire water system using shock chlorination. Shock chlorination involves placing a strong chlorine solution in the well and the complete distribution system.

After conducting a shock chlorination, submit another water sample for testing. The water should test negative before use. More than one shock chlorination treatment may be needed to effectively treat the entire water supply.


A number of different tests are available for different contaminants. At the very least, have the water tested for bacteria and nitrate. Keep in mind that tests for bacteria and nitrate do not guarantee the water is safe or desirable for domestic use, as other contaminants also could be present. Have tests conducted for other substances when specific contaminants are suspected. Some laboratories offer multi-parameter packages that include tests for the most common contaminants of concern. In many situations, these can be good options.

Certified Public Health Environmental Laboratories in Nebraska (Source: Nebraska Department of Health and Human Services)
Name of Lab Certification # Address
Nebraska Department of Health and Human Services Public Health Environmental Laboratory 3701 S 14th St, Lincoln, NE 68502
(402) 471-2122
American Agricultural Laboratory NE-04-06 700 West D Street, McCook, NE 69001
Central District Health Department NE-04-01 1137 South Locust, Grand Island, NE 68801
Enviro Services Inc. NE-04-03 818 S. Beltline Hwy East, Scottsbluff, NE 69361
Metropolitan Utilities Districts NE-04-04 2710 Grebe Street, Omaha, NE 68111
Midwest Laboratories, Inc. NE-04-05 13611 B Street, Omaha, NE 68144

More Detailed Information

For more information on testing and treating water from a well that may have been contaminated by flood water, see these UNL Extension NebGuides:

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