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Why should I be concerned? Surface waters are susceptible to
many sources of contamination. This is particularly true during a
flood event where sewage runoff and overflow from lakes, rivers, and
streams may be carrying bacteria such as E. coli and cholera,
protozoa such as Giardia, and viruses such as hepatitis. If surface
water enters your well, it may contaminate the water that you rely
on for drinking, cooking, washing, and bathing.
What should I do to protect my family from contaminated well
water? If there is a flooding event in your area, your county
health department will issue a precautionary boil water notice
through your local television, radio, and newspapers. |
| In general, if flood waters have
reached your well, or if you notice any change in the appearance or
taste of your water, or even if you are unsure about the impact of
flooding on the water quality in your area, you should boil all of
the water you use for drinking, making beverages, cooking, brushing
your teeth, washing dishes, and washing areas of the skin that have
been cut or injured (Be sure to cool the water first.) The water
should be brought for a rolling boil for at least one minute.
Bottled water may also be used for all of these purposes.
Is my water safe to drink after the flooding subsides? No -- If
your well has been flooded, you must first disinfect it and
contact your county health department for information on how to
sample your water and where to bring the sample for
bacteriological testing.
How do I disinfect my well? It is important to disinfect both
the well and all of the household plumbing to assure that all
infectious agents are killed. If you have water treatment
devices, replace all membranes, cartridges, and filters. Water
softeners and water heaters should also receive special
attention to ensured that they do not reintroduce bacteria into
your plumbing system.
Both amount of chlorine and the length of time you allow it to
remain in your system are important considerations. Common
unscented laundry bleach can be used effectively as a chlorine
disinfectant. Please see chart for
recommended amounts of chlorine bleach to use and follow these
steps:
- If the water is discolored, run the water until it is clear.
- Turn off, then drain your hot water heater -- chlorine
bleach is not as effective in water above 105 degrees.
- Bleed the air from pressure tanks so that chlorinated water
can completely fill and sanitize them. Water softeners, sand
filters, and iron removal filters should be backwashed with
chlorinated water. Remove and replace charcoal filters after the
chlorination process is completed.
- To avoid adding further contamination to the well during the
disinfection procedure, first clean up the work area around the
top of the well. Remove grease, mineral deposits, and other
encrustation from accessible parts of well interior and flush
these surfaces with 1/2 cup of laundry bleach in 5 gallons of
water.
- Turn off the well pump. Remove the cap on a two-inch well,
or the well plug on the rubber seal of a four-inch well. There
are many types of well caps and plugs -- if you have questions
you should contact a licensed well driller. If you have a
submersible pump, you may also want to contact a licensed well
driller for advice on disinfection procedures.
- Consult the chart and pour in the
recommended amount of bleach solution. (Your county health
department may issue additional guidance for your area.) Try to
coat the sides of the casing as you pour. If you get chlorine on
the pump or wiring, flush it thoroughly with fresh water to
prevent later corrosion.
- Re-cap or plug the well opening and wait 30 minutes.
- Turn on and, if needed, reprime the pump. Open all of the
faucets on the system one by one. Allow the water to run until
there is a noticeable smell of chlorine. You may also want to
flush the toilets. If you have outside faucets, you may want to
direct the water away from sensitive plants. If you cannot
detect a chlorine odor, re-chlorinate the system.
- Turn off all of the faucets and allow the chlorine to remain
in the system for at least eight-hours, preferably 10-12 hours.
- Again open all of the faucets and run the water until there
is no chlorine smell.
Is it safe now? The only way to verify that the water is safe
to drink is to have it tested. Although chlorine bleach is
effective against microorganisms, it will not remove chemical
contamination that may have gotten into your well. Contact your
county health department for sampling instructions to get your
water tested.. |
