Well Water Safety After Flooding
If flood water came near your private drinking water well, 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. Wells at greatest risk of contamination from flood water or surface water runoff include:
- Wells located in well pits.
- Dug wells or any wells that do not have a watertight casing.
- Wells that do not have watertight caps.
- Wells that lack a grout seal in the annular space.
- Wells that were submerged with flood water or surface water runoff.
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 (3-4 hours) after the disinfectant has been retained undisturbed in the system 6-8 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 this NebGide for Nebraska's certified laboratories.
- 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.
Did you know?
Cost of Testing a Private Drinking Water Supply
There is no single test to determine the safety of drinking water. It would be costly, and in most cases unnecessary, to test a private water well for the nearly 100 contaminants for which public water supplies are required to test. For example, the price for a complete water analysis at the Nebraska Department of Health and Human Services laboratory is currently $3,827.00. Users of private drinking water wells must decide which contaminants to test for and must order tests accordingly. A water-testing laboratory will only test for contaminants specifically requested.
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 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.