There are steps that you can take to help prevent septic waste from backing up into your home during flooding. Photo: George Hurd, Penn State Extension
Too much water in your drainfield may cause your septic system to overload and may slow down or stop the treatment of wastewater. If this occurs you may run the risk of your septic waste backing up into your home, particularly if your drainfield becomes clogged. In wet weather, a rain-soaked drainfield may become too saturated to operate properly for the effluent to percolate down through the soil. There are steps that you can take before this happens to help protect your system.
As a preventive management step, you should keep stormwater runoff away from your system as much as possible. Water from roofs and driveways should be diverted away from the septic tank and drainfield area. Soil over your system should be mounded slightly to encourage runoff.
A well-maintained septic system is better able to withstand the stresses of heavy rains or flooding. Have your septic system inspected annually. The baffles should be inspected to ensure they are present and not severely corroded. The sludge and scum levels inside the tank should be checked and the drainfield should be periodically checked for odors, wet spots, or surfacing sewage. Your septic tank should be pumped on a routine basis. This is a very important on-going maintenance step.
According to the Minnesota Pollution Control Agency factsheet, "What To Do With Your Septic System During A Flood", if you live in a flood prone area, you should have a licensed plumber install a backflow preventer on the building sewer so sewage cannot backup into your home during a flood. A backflow preventer is recommended as there is some concern a simple check valve may not close properly and sewage may back-up into the home.
You should have a plan to minimize water use in the home in case your septic system including the drainfield is covered with water from heavy rains or flooding. Additional information on managing your septic system during a flood is available from the U.S. EPA publication "Septic Systems - What to Do after the Flood" and the PA DEP factsheet, "What To Do With Your Septic System After A Flood". You can also contact your local municipality or Sewage Enforcement Officer for additional advice and assistance.