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Septic Systems and Flooding Events FAQs

Flooding can impact all parts of the septic system. This includes the septic tank(s) along with the soil treatment area (aka: drainfield/absorption area).

    • Be patient and allow the system to thoroughly dry and restrict water use from the house.
    • Do not pump the septic tank(s) until the surface and groundwater has receded.
    • If the tanks are pumped during high groundwater, it can cause the concrete tanks to become buoyant and start shifting towards the surface. Plastic tanks can collapse or crush under the pressure. This can cause structural damage to the tanks and piping.
    • Have your septic tank(s) and absorption field professionally inspected for any structural damage or clogging.
    • Contact your local health department for a list of professionals that can inspect your septic system.
    • If the tanks are filled with floodwaters, that can introduce fine particles of silt and mix solids that can plug your drainfield pipes.
    • The tanks must be pumped by a licensed septage hauler AFTER the floodwater and groundwater recedes.
    • If your septic system includes a pump chamber and pump, the electrical system should be inspected by a licensed professional to assure all electrical connections, pumps, and alarms are in proper working order before electricity is turned back on.
    • If your system has any pretreatment components, contact your maintenance provider to inspect the system for damage before the system is put back into use.
    • Always take preventative measures and mark your septic tank and absorption area to assure any clean-up activities do not affect the integrity of the septic system.
    • First, you should mark your system to keep off that area until the floodwaters recede.
    • This area could become hazardous and contaminated if the tank structure becomes impaired.
    • It can also be an electrocution risk if a pump chamber is used that contains a pump serviced by electricity.
    • Make sure that electricity to the pump is turned off to prevent electrocution risks.
    • It is best to restrict wastewater from entering into a flooded septic system to prevent backup into the house.
    • Decrease or eliminate water use that discharges into the septic system.
    • Make sure all sump pumps and water softener discharges are NOT connected into the septic system.
    • All gutter downspouts should be directed away from the septic system to carry water away from the site.
    • DO NOT attempt to service a septic system. A septic system contains a potential for disease transmission, dangerous gases, electrical shock and substances that can be hazardous to your health and safety.
    • DO NOT park or drive over any part of the system. The soil can become compacted and the basic function of the system can become restricted.
    • DO NOT place heavy machinery, dumpsters, or building material on any part of the septic system. The tank could collapse from the weight and the pipes can become dislodged in the drainfield.
    • DO NOT leave the opening to a septic tank uncovered. Assure that all the hole openings are immediately secured, repaired or replaced if the covers have shifted, broken, or lost in the flood. This is to prevent debris from falling into the septic tank along with maintaining safety from people falling into the tanks during clean-up activities.
  • If your water well has also been flooded, it could be contaminated. Contact your local health department for questions if your well is safe to drink and how to test the water.

    If you are unsure where your onsite wastewater treatment system (aka: septic system) is, contact your local health department for additional advice and assistance. Local health department information can be found at the Michigan Association for Local Public Health website or by visiting the CDC website. For additional flood safety information, visit the Michigan Department of Health and Human Services Flood Safety Fact Sheet Series.