Flooding after a storm can damage septic systems, causing them to fail. Image: B White, NASA Public Domain

After floods or heavy rains, the soil in your septic system drainfield can become waterlogged. But, for your septic system to treat wastewater, water needs to drain freely in the drainfield. Special care needs to be taken with your septic system after a storm in order to ensure its proper function.

What should you do if flooding occurs?

The U.S. Environmental Protection Agency (EPA) offers these guidelines:

  1. Relieve pressure on the septic system by using it less or not at all until floodwaters recede and the soil has drained. Under flooded conditions, wastewater can’t drain in the drainfield and can back up in your septic system and household drains. Clean up floodwater in the house without dumping it into the sinks or toilet. This adds additional water that an already saturated drainfield won’t be able to process. Remember that in most homes all water sent down the pipes goes into the septic system.
  2. If sewage from the septic tank has backed up into your house, clean up the affected area and disinfect the floor using a chlorine solution of a half cup of chlorine bleach to each gallon of water for thorough disinfection.
  3. Avoid digging around the septic tank and drainfield while the soil is waterlogged. Don’t drive vehicles or equipment over the drainfield. Saturated soil is very susceptible to compaction. By working on your septic system while the soil is still wet, you can compact the soil in your drainfield, and water won’t be able to drain properly.This reduces the drainfield’s ability to treat wastewater and leads to system failure.
  4. If you suspect your system has been damaged, have the tank inspected and serviced by a professional. How can you tell if your system is damaged?  Signs include: settling, wastewater backs up into household drains, the soil in the drainfield remains soggy and never fully drains, a foul odor persists around the tank and drainfield. The tank shouldn’t be opened or pumped if the soil is waterlogged. Silt and mud can get into the tank if it is opened and can end up in the drainfield, reducing its drainage capability. Pumping under these conditions can cause a tank to float or ‘pop out’ of the ground and can damage inlet and outlet pipes. Only a licensed professional should clean or repair the septic tank.
  5. For septic systems with electrical components, make sure to check all the electrical connections for damage before restoring electricity (to pumps, for example).
  6. Have your private well water tested if your septic system or private well were flooded or damaged in any way. Your well water may not be safe to drink or to use for household purposes (making ice, cooking, brushing teeth or bathing). You need to have it tested for total coliform bacteria and E. coli to ensure it is safe to use.

Many county health departments provide testing for bacterial contamination. If they do not offer testing, they can help point you to commercial labs in the area for testing.

The Florida Department of Environmental Protection (FDEP) also maintains a site where you can search for certified water testing labs by county: Certified Water Testing Laboratories

For more information on septic systems and maintenance go to UF/IFAS Septic Systems or EPA Septic Systems

Andrea Albertin