How to Disinfect Your Well

How to Disinfect Your Well

Inexpensive and Effective Procedure to Remove Harmful Bacteria from Private Wells

Author: Environmental Health Staff/Wednesday, December 19, 2012/Categories: Well and Septic, NEWS

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The purpose of disinfecting a dug or drilled well is to destroy all disease causing microorganisms (pathogens) that may be present in the well. If after testing the analysis indicates that your well water is unsatisfactory for drinking or cooking, the following procedure should be used to restore water quality

  • Check the well seal and vent to be sure of good, tight construction.
  • Replace any damaged parts.
  •  Remove the well seal.
  • Mix one gallon of unscented chlorine bleach with three gallons of water in a clean bucket.
  • Pour the solution into the well casing making sure that the inside of the casing pipe is thoroughly rinsed with the bleach solution.
  • To disinfect the well, re-circulate the chlorinated water back into the well casing for 10-15 minutes using a clean garden hose. If you have a water softener, put it on bypass.
  • Replace the well seal and make sure the connection is water-tight.
  • Turn on each water faucet and let them run until you can smell the chlorine bleach at each tap.
  • Turn off the taps and allow the solution to stand in the water lines overnight or at 6 hours.
  • For homes on public sewers, on the following morning simply let each water tap run until the odor of bleach has disappeared.
  • For homes on septic systems, connect a garden hose to an outside tap on the following morning and run the water into the roadside ditch until the odor of the bleach has disappeared then open the taps and let the water run until you no longer detect the bleach odor.

·      Take a new water sample after waiting 3-5 days and bring it to the laboratory for testing. If chlorine is still present, the laboratory will not run the sample and it will be declared invalid but you will be charged. Mark the new sample as a Repeat on the requisition form.

Chlorine compounds are the most popular disinfectant for drinking water because of their potency and effectiveness on a wide range of germs. Chlorine is also easy to use, relatively inexpensive, and persists in a well long enough to kill harmful organisms. The procedure described above should also be used for the disinfection of new wells or following repairs carried out on existing wells.

All water from private wells should be analyzed for bacteria at least once every year. Sample bottles are available at the WCHD Environmental Health Laboratory and branch offices of the health department 8:00 a.m. to 4:00 p.m. Monday through Friday. Environmental Health staff are available for consultation M-F 8:00 a.m. to 4:30 p.m.

Environmental Health Office                         (815) 727-8490

Environmental Health Laboratory                 (815) 727-8517



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Environmental Health Staff

Environmental Health Staff

Environmental Health

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The Will County Environmental Health Department protects public health through programs specifically designed to promote healthy environmental conditions and reduce risks associated with communicable disease.
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