What Happens to your Septic System in a Flood

Flooding and your Septic System

Floods can effect your septic system.

If your home, or the area surrounding your septic system, experiences a flood, your septic system may become waterlogged. Whether caused by the development of a leak in the lid, rising groundwater that enters into the inlet our outlet, or a saturated drainfield that is unable to drain, a flooded septic system is something every homeowner should take seriously. Depending on the elevation of your septic system compared to your lowest toilets or drains , a flooded septic system may lead to sewage backing up into your home. Properly disposing of such hazardous wastewater is essential to keeping your loved ones safe in the event of a flooded septic system. In the event that your septic system becomes flooded, be sure to contact Supeck Septic immediately and follow these measures for protecting you and your loved ones from potentially life-threatening diseases.

Dangers to a Septic System During a Flood

Most septic tanks themselves will not be damaged by a flood. However, because they are below ground, any leaks that allow floodwaters to enter may also allow silt and debris into the system, which can cause damage to other components of your septic system. An inundated septic tank may experience leaks through any opening, like the manhole cover, the inlet or outlet pipes, or the tank cover. These leaks may allow soil and silt to enter into your septic system, which could cause your drainfield to clog. An influx of water into your septic system may also cause the layer of floating solids to rise and plug the inlet and outlet pipes, if not both. Water from a flooded drainfield may also flow backwards into the tank. All of these issues combined may cause your drains to run slowly or not at all, prevent your toilets from working, or cause wastewater to backup into your home.

What to do if Your Septic System Experiences a Flood

During flooding conditions there is little more you can do for your septic system than significantly reduce your home’s water usage. A flooded system may not allow you to flush your toilets or even run your sinks, so you may have to consider evacuating until floodwaters recede. Even if your system is not completely inundated during a flood, conserve water usage as much as you can. As soon after a flood as you are able, you should contact Supeck Septic to have your system checked over to ensure a return to proper functioning.

Do not…!

  • Have your septic tank pumped while high groundwater conditions still remain. Older tanks may collapse, and any tank, but especially those installed relatively recently, may “float to the surface” (i.e. pop out of the ground) when pumped under such conditions.
  • Compact the soil over the drainfield by driving heavy machinery in the area. As a note, you should never drive heavy machinery over your drainfield, but saturated soil is especially susceptible to compaction, which will directly interfere with your system’s functioning and may lead to whole system failure.


  • After flood waters recede, continue to conserve water usage as much as you can. Even if it is not completely underwater, your system will be undergoing significant stresses to its functioning in flooded conditions. Limit how many times you flush the toilet, do laundry off-site, reduce the number of showers and baths each day, and run the dishwasher only when it’s full.
  • Examine all electrical connections, or have them inspected by Supeck Septic, before restoring electricity to your aeration system.
  • If your septic system has backed up into your home, clean the affected areas and disinfect with a solution of ½ cup bleach to a gallon of water.
  • Have your system inspected and serviced by Supeck Septic as soon as you can after floodwaters have receded. Supeck will inspect and service your septic to ensure a return to the full functioning of your system after a flood. This may include pumping your system as soon as it is safe to do so.