Disinfecting a Well

Disinfecting A Well

1. Remove the well cover. Pour the required amount of bleach into the well. (See table below)
2. Run ALL FAUCETS in the house, one at a time, until you smell the chlorine at the faucet. This ensures that the whole system gets disinfected.
3. Connect a garden hose to an outside tap or an indoor tap with the correct threaded fitting. Put the other end of the hose into the well, turn on the faucet, and from time to time move the hose so that the chlorinated water bathes the sidewalls of the well casing. Do this for at least six hours. Then turn off the tap and remove the hose from the well.
4. Replace well cover.
5. Do not use the water for at least twelve hours. Forty-eight (48) hours is optional. Consider taking a week-end vacation!
6. Run the water to waste (not in the septic system) for several hours, or until the chlorine taste is dilute enough to be unobjectionable. The best way to run the water to waste is to use the garden hose mentioned above (item 3). Direct the hose into an area where the chlorinated water will not cause environmental damage or affect the water supply of others. For a typical w ell, this will take three or four hours.
NOTE: To avoid pump overheating and possible damage, turn off the water when flow is at a trickly and wait at least 15 minutes before turning pump on again.
7. After a week of use, retest for bacteria.
8. In some cases, one chlorinating treatment will not be sufficient. Repeat disinfecting procedures as needed.

If your well depth is:

Use this much liquid household bleach

Up to 150 feet One quart

151 feet - 300 feet Two quarts

301 feet and over At least one gallon bleach and 1 cup crushed swimming pool tablets

NOTE: The above table is for wells with a casing six inches in diameter. If the well casing is not six inches in diameter, then figure the bleach amount as follows:

1.Multiply the well diameter in feet by itself. (Square the diameter)
2. Multiply this result by the depth (in feet).
3. Multiply the final number by 0.0302. This will give you the number of quarts of bleach required for disinfection. Round the number to the nearest higher whole number to be absolutely safe. It is better to over-chlorinate than to under-chlorinate.

A Reminder About New Wells

New wells must be thoroughly (and often repeatedly) disinfected. The construction process usually leaves the well grossly contaminated. If a new well has been thoroughly disinfected, pollution can persist for a long time. By following the suggestions above carefully, you can frequently achieve a properly disinfected supply after the first cleaning.

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If your well depth is:	Use this much liquid household bleach
Up to 150 feet	One quart
151 feet - 300 feet	Two quarts
301 feet and over	At least one gallon bleach and 1 cup crushed swimming pool tablets