Bacteria and Other Microorganisms in Household Water

  • Parrott, Kathleen;
  • Ross, Blake;
  • Woodard, Janice

Table of Contents


  1. Pour the proper amount of liquid chlorine bleach or powdered chlorine mixed with several gallons of water directly into the well. (See Tables 1a and 1b).
  2. Connect a garden hose to a nearby faucet and wash down the inside of the well for about 15 minutes.
  3. Open each faucet inside and outside the house one at a time and let the water run. Close the faucet after a strong odor of chlorine is detected. If a strong odor of chlorine cannot be detected, add more chlorine to the well.
  4. Let the water stand for 12 to 24 hours. Do not run any water at this time.
  5. Flush the system of remaining chlorine. Do this, one faucet at a time, starting with the outside faucet(s). This order will reduce the load on your septic system. Let each faucet run until chlorine odor is no longer noticeable.

  1. Scrub the walls of the spring box with a solution of 1/2 cup of liquid chlorine bleach (1 tablespoon calcium hypochlorite) and as much water as needed to clean the area.
  2. For each 100 gallons of water to be disinfected, mix 1 1/2 quarts of liquid chlorine bleach (3 ounces calcium hypochlorite) with several gallons of water. (A spring box holds 7 1/2 gallons of water for each 1 cubic foot of storage space.)
  3. Follow step 3 in directions given for shock chlorinating wells.
  4. Let the water stand in the plumbing system for at least 12 hours. If the spring flow is low enough, it may be possible to keep the disinfectant in the spring box for the required time. Otherwise, you will have to add disinfectant continously throughout the period.
  5. Follow step 5 in directions given for shock chlorinating wells

Publication #: 356-487

Kathleen Parrott, Extension Specialist, Housing
Blake Ross, Extension Specialist, Agricultural Engineering
Janice Woodard, Retired Extension Specialist, Home Management and Equipment.

Disclaimer and Reproduction Information: Information in NASD does not represent NIOSH policy. Information included in NASD appears by permission of the author and/or copyright holder. More