Septic Systems—What to Do after the Flood
Where can I find information on my septic

Please contact your local health department
for additional advice and assistance. For more
information on onsite/decentralized wastewater
systems, call the National Environmental Services
Center at (800) 624-8301 or visit their website at

Do I pump my tank during flooded or
saturated drainfield conditions?

No! 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.

      if my septic system has been used to dispose wastewater from my business (either a
  iome-based or small business)?

In addition to raw sewage, small businesses may use their septic system to dispose of wastewater
containing chemicals. If your septic system that receives chemicals backs up into a basement or drain
field take extra precautions to prevent skin, eye and inhalation contact. The proper clean-up depends
of what chemicals are found in the wastewater. Contact your State or EPA for specific clean-up
. information.

' What do I do with my septic system after the flood?

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.
      •  Only trained specialists should clean or repair septic tanks because tanks may contain
      dangerous gases. Contact your health department for a list of septic  system contractors who work
      in your area.
      •  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

     • Pump the septic system as soon as possible after the flood. Be sure to purnp both the tank and
     lift station. This will remove silt and debris that may have washed into the system.  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.
     • 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.                                v,
     • 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.                                                                  ^
     •• Check the vegetation over your septic tank and soil absorption field. Repair erosion damage
     and sod or reseed areas as necessary to provide turf grass cover.                           ;

Remember: Whenever the water table is high or your sewage system is threatened by flooding
there is a risk that sewage will back up into your home. The only way to prevent this backup is
to relieve pressure on the system by using it less.

    1 . What are some suggestions offered by experts for homeowners with flooded septic systems?

    2. Use common sense. If possible, don't use the system if the soil is saturated and flooded. The
    wastewater will not be treated and will become a source of  pollution. Conserve water as much as
    possible while the system restores itself and  the water table fails.

    3. Prevent silt from entering septic systems that have pump chambers. When the pump chambers
   . are flooded, silt has a tendency to settle in the chambers and will clog the drainfield  if it is not

    4. Do not open the septic tank for pumping while the soil is still saturated. Mud  and  silt may enter
    the tank and end up in the drainfield. Furthermore, pumping out a tank that is in saturated soil
    may cause it to "pop out" of the ground. (Likewise, recently installed  systems may "pop out" of the
    ground more readily than older systems because the soil has not had enough time to settle and

    5. Do not dig into the tank or drainfield area  while the soil is still wet or flooded. Try to avoid any
    work on or around the  disposal field with heavy machinery while the soil is still wet. These activities
    will ruin the soil conductivity.

    6. Flooding of the septic tank will have lifted the floating crust of fats and grease in the septic tank.
    Some of this scum may have floated and/or partially plugged the outlet tee. If the septic system
    backs up into the house check the tank first for outlet blockage. Clean up any floodwater in the
    house without dumping it into the sink or toilet and allow enough time for the water to recede.  <
    Floodwaters from the house that are passed through or pumped through the septic tank will cause
    higher flows through the system. This may cause solids to transfer from the septic tank to  the
    drainfield and will cause clogging.                                                       ;  ,

    7.  Locate any electrical or mechanical devices the system may have that could  be flooded to avoid
    contact with them until they are dry and clean.                                            |,

    8.  Aerobic plants, upflow filters, trickling filters, and other media filters have a tendency to clog
    to mud and sediment. These systems will need to be washed  and raked.
Office Water (4606 M)                    EPA 81 6-F-05-029 September 2005