Flooding
of a private sewage system can be a hazardous situation for
homeowners. It may lead to a back-up of sewage in the home,
contaminated drinking water and lack of sanitation until the
system is fixed. While you don't have control over rainfall
or flooding in your area, you can prepare for high water problems
and respond appropriately to emergency flooding.
When
flooding or saturated soil conditions persist, a private sewage
system cannot function properly.
Soil
treatment systems for wastewater rely on aerobic (with oxygen)
regions to reduce the amounts of chemicals and living organisms
(viruses, bacteria and protozoa). When the soil is saturated
or flooded, those hazardous materials can enter the groundwater
and your drinking water supply.
If you
are prepared when flooding occurs, your family can be safe
and your system should survive. To prepare for a flood you
should:
- Make
sure all septic tanks are full of liquid. The high-water
season is not the time to have tanks pumped; empty tanks
are buoyant and may "pop" out of the ground during
flooding.
- Plug
floor drains, if necessary, to keep sewage from backing
up into the basement. Floodwaters may still enter the
basement through cracks and seams, however.
- Discontinue
use of your private sewage system. Use portable toilets,
if possible, or use any large container with a tight-fitting
lid for a temporary toilet. Line the container with a plastic
bag. After each use, add chlorine bleach or disinfectant
to stop odor and kill germs. If necessary, bury wastes on
high ground far away from your well.
- Remember
that a well may become contaminated during a flood. Therefore,
DO NOT DRINK THE WATER. Drink bottled water, or disinfect
water before drinking. Contact your local health department
for disinfection instructions.
- Do
not bathe or swim in floodwater. It may contain harmful
organisms.
- Shut
off power to a sewage lift pump if you have one in the house
or in a pump chamber (mound, in-ground pressure, at-grade
systems).
- Do
not use the sewage system until water in the disposal field
is lower than the water level around the house.
- If
you suspect damage to your septic tank, have it professionally
inspected and serviced. Signs of damage include settling
or inability to accept water. Most septic tanks are not
damaged by a flood since they are below ground and completely
covered. However, sometimes septic tanks or pump chambers
become filled with silt and debris, and must be professionally
cleaned. If tile lines in the disposal field are filled
with silt, a new system may have to be installed in new
trenches. Because septic tanks may contain dangerous gases,
only trained specialists should clean or repair them. Wisconsin
code requires licensed plumbers for any repairs.
- Discard
any items that are damaged by contaminated water and cannot
be steam cleaned or adequately cleaned and disinfected.
- Do
not pump water out of basements too quickly. Exterior
water pressure could collapse the walls.
- If
sewage has backed up into the basement, clean the area and
disinfect the floor with a chlorine solution of one-half
cup of chlorine bleach to 1 gallon of water.
- Contact
the county health department or county Extension office
to obtain a drinking water test kit. (See the fact sheet
"Water Contamination in Private Wells.") Do not
drink the water until it has been tested and is safe.
Additional resources:
Your county family living agent, your county code administrator, your local health department, the Wisconsin Bureau of Building Water Systems, Department of Industry, Labor and Human Relations.
Related publications:
UW-Extension publication "Care and Maintenance of Residential Septic Systems," (B3583).
Disclaimer and Reproduction Information: Information in
NASD does not represent NIOSH policy. Information included in
NASD appears by permission of the author and/or copyright holder.
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