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Water Disinfection Instructions

For disinfection of your water supply, for E. coli or Total Coliform, follow the instructions below.

  • Pour either chlorine granules or laundry bleach (see below table) into the well. Attach a hose to a nearby faucet and direct back in to the well. Open the faucet, allowing water to flow back in to the well and wash down the well casing, pipes, and other equipment. Let water run, back in to the well, for approximately one hour, or until strong chlorine odor is present.
  • After allowing water to run, open all faucets (inside and outside) linked to the well. Let faucets run until a chlorine odor is present. Then close all faucets and let chlorinated water remain in system for at least 24 hours. Do not use the water during this time.
  • After a 24 hour period: to avoid septic tank over load rinse water should run into a field or ditch, away from any streams or lakes. Attach a hose to an outside faucet and let water run until no chlorine odor can be detected. Chlorine may kill grass or shrubs.

*Per each 10ft of water depth in well add one or the other of the following:


           Amount of Chlorine Granules*

       Amount of Laundry

        2” – 8”

                             1 ounce

                     1 pint

      10” – 14”

                            3 ounces

                    3 pints

      16” – 20”

                            7 ounces

                    7 pints

      22” – 26”

                           12 ounces

                   12 pints

      28” – 30”

                           16 ounces

                   16 pints


                           24 ounces

                   24 pints


**Instructions from Nebraska Health and Human Services.

You should retest your water supply for total Coliform and E. coli bacteria no sooner than 3 weeks from time of chlorination. It is important to retest after 3 week to determine if there is a recontamination of the well which could indicate a larger problem such as a breach in your system which is letting in contaminants.

For more detailed information on shock chlorination, request the NebGuide, G95-1255-A “Shock Chlorination of Domestic Water Supplies,” from your cooperative extension office or find it on the internet at