Drinking Water Disinfection
How to Disinfect Your Water System
Use a chlorine bleach solution to disinfect your water supply after a flood, after construction or repair work (including replacing the pump), or when a water test result shows contamination with bacteria.
CAUTION:- Keep children and pets away from chlorine and chlorinated water.
- Protect eyes and skin from chlorine. Avoid contact during disinfection.
- Strong chlorine solutions may damage rubber and polybutylene gaskets and fittings.
Steps to Disinfection:
- Before you begin, disconnect, detour around, or remove any water treatment devices – such as carbon filters, water softeners or reverse osmosis units.
- Carefully and slowly pour 1 gallon of unscented regular household chlorine laundry bleach for every 525 gallons of water into your dug or drilled well. This means using 1 gallon of bleach for every 10 feet of 36-inch diameter dug well or every 350 feet of 6-inch diameter drilled well.
- If possible, run water through a garden hose back into the well for 10 to 15 minutes to help mix the chlorine with the well water, and to wash down the inside surfaces of the well.
- If possible, scrub the inside of the casing of a dug well or spring with a clean brush and a strong chlorine solution. (Mix one part household laundry bleach to four parts water.) Be sure to use rubber gloves, skin and eye protection.
- Recap the well. Go into your home and turn on one faucet at a time throughout the house. Run the water until you smell a strong chlorine odor, then turn the faucet off.
- It takes time for chlorine to disinfect, so it’s important to keep the chlorinated water in your system for 12 hours. After 12 hours, connect a hose to an outside tap, and begin to drain the chlorinated water from the well into to a safe outdoor location such as a graveled driveway or into a brushy area.
CAUTION:
• Do not drain chlorinated water onto a lawn or garden.
• Do not let chlorinated water to reach a river, stream, pond or lake because chlorine can kill fish.
- Run the water through the hose at less than full flow, or turn off the hose every so often so you don’t run your well dry. Continue flushing through a hose or home faucets until the strong odor of chlorine gets weaker or is gone.
Sometimes the chlorine odor will stay for three to five days. Using household water in a normal fashion will help flush out the remaining bleach.
CAUTION:
• Some people with sensitive skin or eyes will want to bathe or shower elsewhere. This will vary depending on the well.
- Collect water for total Coliform/E. coli testing (KIT A) two to three days after the chlorine odor is gone. Continue to either boil water or get drinking water from a known safe source until test results show your water is safe again.

