From the ADEC/Drinking Water Program
1) During this procedure the water will not be drinkable so plan to do it late at night or at other times when there is little need for water. Obtain one-half gallon of household bleach (unscented) which contains 5-6% sodium hypochlorite. Large diameter or very deep wells may require more bleach. Dilute the chlorine in a large bucket of water.
2) Remove the sanitary seal and pour the chlorine solution down the well casing. Using a clean hose, run water down the casing until you smell chlorine in the water from the hose. Turn off the hose and replace the sanitary seal.
3) Open each tap in the house until you smell the chlorine, then close the valve. Your are trying to get the chlorine solution to all parts of the plumbing. Do the same for hot water taps and flush toilets until chlorinated. If there are any in-line filters, they should be removed, and replaced with new filters after the disinfection is completed.
4) Hold the chlorine in the pipes for at least two (2) hours, preferrably overnight.
5) Open all taps and flush out the chlorine solution until you can no longer smell it at any of the taps. Your well and distribution system should now be disinfected.
6) Follow-up sampling should be done within a week to insure that the disinfection procedure was successful. ADEC Drinking Water personnel will advise public water suppliers (PWS) of their sampling requirements.
NOTE: Large amounts of chlorine can damage the resin in water softeners, so if there is a softener, it should be by-passed before disinfecting the plumbing. You should contact the manufacturer or distributor for the correct method for disinfecting the softener.
If you have any questions regarding the above procedure, please contact us.
ADEC/Drinking Water Program– (907) 269-7518
555 Cordova Street, Anchorage AK 99501,