Steps to Disinfecting Your Well Water

You have received a positive water sample result for coliform bacteria from the Monroe County Health Department Laboratory or the Michigan Department of Environmental Quality (MDEQ) laboratory.

  • Set aside 12 hours of time that the well will not be in use.
  • Purchase a gallon of bleach solution (i.e. Chlorox laundry bleach, pool bleach-5 1/4% sodium hypochlorite). Do not use bleach with additives such as fresh scent. Remove the cap on the top of the well casing.
  • Pour the gallon of bleach into the well (between the small pipe and the large outer casing pipe).
  • Attach a garden hose to an outside faucet. Turn hose on and when you can smell the bleach odor, place the other end of the garden hose back into the top of the well. You want the pump to turn on and off like a surge effect. Let it run for about 3 to 4 hours. This will re-circulate the chlorine inside the well.
  • Turn off the hose and remove it from the well. Replace the cap on the well.
  • If the plumbing is not in place, stop here and allow the chlorine to sit in the well at least overnight and continue at next.
  • Inside the house, turn the sample tap at the pressure tank on. When you detect (smell) chlorine, turn the faucet off. Go to the second closest faucet and do the same thing. Continue until all taps have evidence of chlorine in them.
  • Leave the chlorine in the pipes overnight (8 hours). Try not to use any water because contact time is important.
  • In the morning, take the garden hose attached to the outside tap and place it out in the driveway or to a ditch. Let it run for 4 to 6 hours to remove all the chlorine out of the well. If you smell chlorine after 6 hours, let it run until the odor is gone. Do not run this water into your leach field.
  • Turn all faucets in the house on to remove the chlorine left in pipes.
  • Call our office to have another sample collected if we collected the first sample or bring in your own sample if you collected the first sample.

Disinfecting Small Amounts of Water

  • Boil the water at full boil for at least two minutes. To remove the "flat" taste from the boiled water, cool; poor it back and forth between two clean receptacles several times to permit the water to pick up carbon dioxide from the air.
  • A simple and easy alternate method for making water safe for drinking is to disinfect it with chlorine. Add three drops of any common laundry bleach such as Clorox (active ingredient 5 ¼%), to each gallon of clear well water, mix and let stand for 30 minutes before using.
  • Do not use bleach with additives, such as fresh scent, lemon, etc.

If you have any questions, please call the Monroe County Health Department, Monday through Friday, 8 am to 5 pm at 734-240-7900.