Well Water Safety

If your private drinking water well has been impacted by floodwater,  your water supply may have been contaminated with pollutants carried in the flood water. In addition, wells can be contaminated by surface water runoff even if the surrounding area is not flooded. Do not use the water for cooking, drinking, or brushing teeth until laboratory analysis confirms it is safe. (See water treatment options for household amounts and shock chlorination for well disinfection.)

Wells at greatest risk of contamination from floodwater or surface water runoff include:

  • A well located in a pit. This is where a wellhead, and possibly other well equipment are located in a below ground enclosure.
  • Dug wells or any wells that do not have a watertight casing.
  • Any well that does not have a watertight secure cover or cap
  • Any well constructed prior to 1986. Prior to water well construction regulations in Nebraska, construction practices did not have a mandatory grout seal in the annular space around the well casing, making it less resistant to having surface runoff or floodwaters enter the well.
  • Any well that was submerged with floodwater or surface water runoff.

Protect Wells from Flood Water

  • Disconnect the power supply at the breaker panel.
  • 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 (NDSU Extension resource)
  • Water-Inflated Flood Barriers (LSU Extension resource)

Managing Wells After Flooding

If you think your private drinking water well was impacted by flood water:

  • Do not use the water for cooking, drinking, or brushing teeth until laboratory analysis confirms it is safe.
  • Contact a licensed well contractor. The contractor should:
    • Inspect the well.
    • Clean out any debris or sediment that entered the well.
    • Disinfect the well with shock chlorination. The system must be flushed (three to four hours) after the disinfectant has been retained undisturbed in the system for six to eight hours to remove any debris and flush contaminates from the water system before testing for drinkability.
  • Then, contact a certified testing laboratory and tell them you want to have your private water supply tested for bacteria. They will provide a test kit with detailed instructions. (See list of certified laboratories in the Water Testing Kits section.) 
  • Don't use the water from your well until the laboratory has informed you that it is safe and free of bacterial contamination. It may be necessary to repeat the disinfection and testing process several times before the well is free of contamination.

If flood water came close to your well (100 feet or less) but did not reach the well, have your water tested as a precaution.

Water Testing Kits

The State of Nebraska Department of Health and Human Services(NDHHS) Public Helath Environmental Laboratory certifies other public health environmental laboratories in Nebraska for drinking water analaysis of public water systems throughout the state. It is recommended that private well owners also use a certified laboratory to test their well water. Below is the information for the NDHHS Public Health Environmental Laboratory

When ordering a kit from any of the laboratories listed below, request a Bacteria Kit that will give a Numerical Count result, otherwise known as a Coliform by Quantitray test. 

 http://www.nebraska.gov/dhhs/water-test-kits/private.html.

Certified Public Health Environmental Laboratories in Nebraska that Accept Private Well Samples (Source: NDHHS Public Health Environmental Lab)
Name of Lab Phone    Address Certified for Analyses

Nebraska Public Health Environmental Laboratory

 402-471-3935

3701 South 14th St., Lincoln, NE 68502

To order test kits, visit: http://www.nebraska.gov/dhhs/water-test-kits/private.html

 Certified by the United States Environmental Protection Agecy (U.S. EPA) for drinking water analyses

American Agricultural Laboratory 

 308-345-3670

700 East D Street McCook, NE 69001

 Total Coliform/E.coli by Colilert SM9223B, Nitrate/Nitrite EPA 353.2
Central District Health Department 308-385-5175

1137 South Locust Grand Island, NE 68801

 Total Coliform/E.coli by Colilert SM9223B
Enviro Services Inc. 308-632-3933

818 S. Beltline Hwy East Scottsbluff, NE 69361

 Total Coliform/E.coli by Colilert SM9223B
Midwest Laboratories, Inc. 402-334-7770

13611 B Street Omaha, NE 68144

 Total Coliform/E.coli by Quanti-tray 2000 SM9223B, Nitrate as N by EPA 300.0, Nitrite as N by SM4500-NO2-B, Nitrate/Nitrite as N by EPA 353.2, Copper by EPA 200.8, Lead by EPA 200.7, VOCs by EPA 524.2, Floride by EPA 300.0

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:

Information provided by current University of Nebraska-Lincoln Extension Associate, Becky Schuerman and Extension Specialist, Bruce Dvorak, as well as former Extension Educator, Sharon Skipton.