Private Well Disinfection Directions
If your water sample showed bacteriological contamination,
(unsatisfactory for coliform bacteria, fecal coliform or
E.coli), you can follow the directions below for disinfecting
the well and pipes. The water should be resampled about one
week after bleaching (i.e. chlorinating) the well.
Note: Do not drink the water if coliform bacteria were found
by the laboratory. The coliform bacteria indicate there may
be a potential risk of illness if you consume the water.
Boil the water for 10 minutes before drinking or using in
food preparation to avoid the risk of illness.
- Use one gallon of regular (no perfumes: i.e. “lemon
household bleach that contains sodium hypochlorite. WARNING:
There are new household bleaches on the market that do not contain any
Read labels carefully and look for bleach that contains sodium
hypochlorite as an ingredient. Please call our office if you
have any questions.
- Mix the bleach in 5 to 10 gallons of clear water.
Pour half of it directly into the well. If possible, pour
remainder in so that the sides of the casing are washed
down. To fully distribute the bleached water in the well,
garden hose down the well and let it run for 5-10 minutes.
This will circulate the bleached water from the well,
through the hose and back to the well again.
- After the bleach is added, turn on some taps in the
house until the odor or taste of bleach can be detected,
them off. Do the same for all other taps and faucets.
If you have a treatment system for your water, you may
to by-pass the treatment unit so it is not damaged by
the bleach. If you share the well with someone else, let
know you are disinfecting the well so they do not inadvertently
do a load of laundry or take a shower with the bleach
- Allow the bleach water to remain in the well and pipes
overnight or for 24 hours if possible. Turn on the outside
taps (to avoid over
loading the septic system) until the smell of bleach
can no longer be detected. Then do the same with the
- After about 1 week of use, or after bleach is not
detected with a test kit, submit another sample to
Well Construction Features:
A well constructed as follows will help improve water quality:
- A tight cover with a screened vent is needed to keep
contaminated surface water, debris, and insects from
entering the well.
- The well casing should rise at least 6 inches above
the ground surface to protect it from flooding or ponding
- A water-tight casing with solid joints should be sealed
on the outside with bentonite clay or cement to a minimum
of 18 feet below the ground. Finding a copy of the driller's
well report will help confirm the proper construction
of your well. Our office has some driller's well reports
file, otherwise contact the driller or previous owners.
- The well should be located at least 100 feet from
any source of contamination such as a septic drainfield,
manure storage and spreading, or stream and lake.
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