Natural Disaster Assistance for Missouri Citizens - Restoring Drinking Water

Department of Natural Resources fact sheet
03/2020
Department of Natural Resources Director: Carol S. Comer
PUB764

Contact your public water supply directly for further information and consult the local news media for notification when any health advisories have been issued or lifted. Your local water supplier has the most up-to-date information about problems in your area, such as broken water mains, low water pressure or any other possible sources of contamination. As long as adequate water pressure has been maintained through the flood, you should need only to flush your water pipes.

Flushing Home Water Lines

Disinfection of Unsafe Drinking Water

The following procedures will destroy the usual bacteria and other microorganisms that may be present in water obtained from a contaminated public water supply system or from alternate emergency sources. Boiling is best way to disinfect unsafe water. If chemical disinfection is the only option, use of bleach is preferable to iodine.

Heat Disinfection (boiling):

Chemical Disinfection:

If boiling is not possible, strain the water through a clean, tightly woven cloth into a clean container to remove any sediment or floating matter and purify it with one of the following chemicals. Choice of chemical is based on availability:

Available Chlorine Clear Water Cloudy Water
4 to 6 percent *
1/8 teaspoon per gallon
1/4 teaspoon per gallon

* common household bleach

Purified Water Storage

Water purified by either boiling or chemical disinfection should be stored in clean, noncorrodible, tightly covered containers. Containers suitable for water storage include empty vinegar bottles, soft drink jugs and plastic milk containers that have been thoroughly washed and rinsed with the purified water.

Freezing does not disinfect water; ice cubes must be made from water disinfected as described above.

If You Have a Private Well

Wells that are destroyed, totally filled with mud or suffered extensive damage must be plugged because they may cause further damage to the groundwater supply. If you want to have the same well re-drilled, you must contact a permitted water well driller.

Wells that are partially damaged or partially filled with mud can be cleaned out by a permitted water well driller or pump installer. They can also determine if other repairs are necessary.

Wells that are undamaged should be disinfected following the procedures listed below. If muddy water is present, contact a permitted water well driller for use and start-up procedures.

You can find a permitted water well driller or pump installer in your area at MoWells or a list of permitted contractors is available from the Department’s Well Installation Section at 573-368-2165.

Private Well Emergency Disinfection Procedures

  1. Pump well until water is clear.
  2. Pour one gallon of liquid bleach into the top of the well, making sure to wash down the inside of the well casing with water.
  3. Pump chlorinated water through all household water lines until there is a noticeable chlorine odor. If chlorine odor is not detected, add additional chlorine until you smell it.
  4. Wash down the interior and the exterior of the well with chlorinated water using a hose.
  5. Let chlorinated water stand in the well and in pipes for 24 hours.
  6. Run water until the chlorine smell is no longer detectable.
  7. Have water tested for bacteria. Any water for temporary use should be boiled for three minutes for drinking until you receive satisfactory test results.
  8. If water fails the bacteria test, rechlorinate your well and retest.
  9. Before using the water for drinking, you should have two consecutive safe bacteria samples. These samples should be taken at least 48 hours apart. Caution: Use caution when working on your well to avoid electrical shock from the pump

For More Information

Missouri Department of Natural Resources
Public Drinking Water Branch
P.O. Box 176
Jefferson City, MO 65102-0176
800-361-4827 or 573-751-5331
www.dnr.mo.gov/env/wpp/dw-index.html

Central Field Operations - 573-522-3322

or your nearest regional office at:

Kansas City Regional Office 816-251-0700
Northeast Regional Office - Macon 660-385-8000
Southeast Regional Office - Poplar Bluff 573-840-9750
Southwest Regional Office - Springfield 417-891-4300
St. Louis Regional Office 314-416-2960

A map of regional offices is available on the Department’s website.