Well Water System Disinfection

Should your well need disinfection a well contractor can provide this service. You can disinfect your own water supply using ordinary chlorine bleach. For the average home well, one to two gallons of bleach will be adequate. Be sure to use regular bleach, not "lemon scented" or other modified bleach products.


  1. Your well must be in good condition to prevent contamination. Check the well cap and upper well casing to be certain of tight construction. Replace any damaged parts. Remove the well cap.
  2. Mix a gallon of bleach in a bucket with five gallons of water. Water drawn from the contaminated well is satisfactory. Pour the solution directly into the well. Run a garden hose into the well and recirculate the water until you smell bleach in the water coming out of the hose. Hose down the inside wall of the well casing. Remove the hose from the well. Replace the well cap. Check to see that the well cap has a good fit.
  3. Turn on each water faucet successively throughout the distribution system. Let the water run until you smell bleach. Turn all faucets off.
  4. After two hours, run each faucet for ten seconds and close it again. Then, allow the solution to stand overnight. The water should not be used except for flushing toilets.
  5. On the following morning:
    1. If you have a septic system, connect a garden hose to an outside water faucet and run the water into a road ditch until the bleach odor disappears. Then run each tap inside the house to rid the system of lingering chlorine.
    2. If you have public sewers, run each tap until the bleach odor disappears.
  6. Boil all drinking water, or use bottled water until you receive a satisfactory laboratory report.  Otherwise, water may be made safe for drinking by putting ten drops of bleach in each gallon of water used.  Use the water for non-drinking and non-food purposes for two days, and then re-test your water. Do not test your water as long as the odor of the bleach remains.