Floods and Septic Systems

Reduced capacity or total failure of an on-site sewage system (commonly known as the septic system and drainfield) can result from a flood event. The large amount of floodwater can damage the system and prevent the system from effectively treating sewage by saturating the soils of the septic system's drainfield. Floodwater can enter the system and force solid materials into the drainfield or create a sewage back-up. 

Before the Flood

  • Have accurate records of your septic system including (tanks and drainfield) locations.
  • Keep your septic system in good condition with routine maintenance.
  • Decrease your wastewater use if heavy rains or flooding is possible.
  • Identify alternate wastewater facilities such as commercial laundry and public restrooms.

During the Flood

  • Don't use the septic system.
  • Don't send any floodwater into the septic system and drainfield.
  • Stop using your wastewater facilities such as toilets, showers, sinks, washing machine, and dishwasher. Learn more about toilet use during an emergency
  • Don't dig in the drainfield area.
  • Avoid working around the drainfield with heavy machinery while the soil is saturated.

After the Flood

  • Inform your local health department if your septic system or drainfield was impacted.
  • Check for any backed-up or surfacing sewage.
  • Disinfect any areas exposed to sewage. Learn more about cleaning up after sewage spills
  • Don't drive equipment near or over drainfield or dig into drainfield while the soil is wet.

After the Flood Water has Receded and the Drainfield Soil has Dried

  • Have the septic system and drainfield evaluated and determine the condition by a licensed on-site sewage system professional.
  • Any damage to your septic system or drainfield must be repaired by a licensed on-site sewage system professional.
  • Septic tanks should be checked and pumped out if necessary.
  • Ensure any filters are not clogged with sediment or debris.
  • Check electrical connections for damage and ensure they are dry.
  • Test and observe the functionality of the septic system and drainfield.

More Resources

Signs of Septic System Failure

Floods: Be Safe, Be Prepared