Protecting your septic system after a flood

With one in five U.S. households depending on septic systems to treat their wastewater, knowing how to protect your system after a major flood could save your system and expensive repairs.

Many households and businesses find themselves in flood situations. With any property flooding, it is important to take steps to protect your onsite septic wastewater system to avoid costly mistakes. The U.S. Environmental Protection Agency (EPA) has updated its “Septic System – What to do after the Flood brochure.” This brochure gives a lot of good information and tips to help the home and business owner do the right things to reduce the potential for further damage.

Here are some of the tips found in the brochure:

Do not pump the tank during flooded or saturated drainfield conditions. At best, pumping the tank is only a temporary solution. Under worst conditions, pumping it out could cause the tank to try to float out of the ground and may damage the inlet and outlet pipes. The best solution is to plug all drains in the basement and drastically reduce water use in the house.

Once floodwaters have receded, there are several things homeowners should remember:

  • Do not drink well water until it is tested. Contact your local health department.
  • Do not use the sewage system until water in the soil absorption field is lower than the water level around the house.
  • Have your septic tank professionally inspected and serviced if you suspect damage. Signs of damage include settling or an inability to accept water. Most septic tanks are not damaged by flooding since they are below ground and completely covered. However, septic tanks and pump chambers can fill with silt and debris, and must be professionally cleaned. If the soil absorption field is clogged with silt, a new system may have to be installed.
  • If sewage has backed up into the basement, clean the area and disinfect the floor. Use a chlorine solution of a half cup of chlorine bleach to each gallon of water to disinfect the area thoroughly.
  • Do not compact the soil over the soil absorption field by driving or operating equipment in the area. Saturated soil is especially susceptible to compaction, which can reduce the soil absorption field's ability to treat wastewater and lead to system failure.
  • Examine all electrical connections for damage before restoring electricity.
  • Be sure the septic tank's manhole cover is secure and that inspection ports have not been blocked or damaged.

For more information on septic systems, contact your local health department, county Cooperative Extension Service or state environmental agency.


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