After flooding at your Concord property, use the septic system as little as possible until floodwater has receded and the soil around the tank and drainfield is no longer saturated. Keep people and pets away from sewage or standing water, avoid flooded electrical equipment, and do not open or pump the tank while the ground is flooded. Once conditions are safe, have a qualified septic professional inspect the tank, lids, piping, pump equipment, and drainfield before normal use resumes.
What should you do first after a septic system floods?
Start by protecting people, then reduce the amount of wastewater entering the system. Floodwater may contain sewage, and a saturated drainfield may be unable to accept more liquid. Water used inside the house can back up through plumbing or reach the ground without adequate treatment.
- Keep children and pets away from standing water, wet soil over the septic area, and any visible sewage.
- Postpone laundry, dishwasher cycles, long showers, baths, and other high-volume water use.
- Flush toilets only when necessary. Use a temporary toilet if local emergency officials recommend one.
- Fix or shut off running toilets and leaking fixtures if you can reach them safely.
- Do not send indoor flood cleanup water into a sink, toilet, or floor drain.
- Do not walk onto a loose or damaged tank cover.
The CDC guidance for septic systems after floods advises reducing nonessential water use, flushing as little as possible, avoiding standing water that may contain sewage, and staying away from septic electrical devices until they are dry and clean.
Flood recovery is different from an ordinary wet-weather slowdown. Our guide to septic problems after heavy rain explains how rainfall can saturate a drainfield even when floodwater never crosses the property. This article covers the added risks that follow actual flooding, including contaminated water, displaced parts, silt, erosion, and electrical damage.
Should you pump a septic tank while the ground is flooded?
No. Do not pump the septic tank while the tank area or drainfield is flooded or saturated. Removing the tank contents changes the balance between the tank and the surrounding groundwater. In the wrong conditions, an emptied tank may shift or rise and damage its inlet or outlet pipes.
Opening the tank during a flood can also let mud and silt enter. Heavy equipment can compact saturated soil above the drainfield and reduce its ability to accept and treat wastewater. Keep pumping trucks, excavators, cars, and other traffic off the tank and drainfield until the soil can support them.
The EPA septic flood recovery guidance says not to pump during flooded or saturated drainfield conditions. It also warns that pumping under those conditions can cause a tank to float and damage connected pipes. Wait for the floodwater and high groundwater to recede, then let a septic professional decide when pumping is safe.
When can you begin using the septic system again?
A dry lawn surface is not enough by itself. Soil below the surface may still be saturated, and groundwater may remain high after visible floodwater disappears. The EPA advises waiting until the water in the soil absorption field is lower than the water level around the house.
Resume water use gradually after the water has receded and any suspected damage has been inspected. Start with necessary toilet and sink use rather than several showers, laundry loads, and a dishwasher cycle on the same day. Watch indoor drains, the tank area, and the drainfield as the system receives water again.
Stop adding water and request service if several drains slow down, toilets gurgle, a floor drain overflows, sewage backs up, an alarm sounds, or wastewater appears outside. If sewage enters the home, follow the immediate steps in what to do when a septic system backs up into the house.
What should a post-flood septic inspection cover?
A post-flood inspection should look for more than a full tank. Flooding can affect access covers, tank position, pipes, pump chambers, controls, filters, distribution parts, and the soil surface above the drainfield. Give the inspector any permit drawing, maintenance record, or photo that shows how the property looked before the flood.
Ask the professional to check:
- Tank position and structure. Look for settling, shifting, exposed areas, cracks, or signs that water entered through a lid, riser, seam, or damaged connection.
- Lids and inspection ports. Confirm that covers are secure and that openings have not been blocked, broken, or displaced.
- Inlet and outlet flow. Flooding can move the scum layer and may leave material near the outlet tee or filter.
- Pump chambers and mechanical parts. Check for silt, debris, unusual water levels, damaged floats, pump faults, or blocked discharge piping.
- Electrical equipment. Have flooded panels, junctions, alarms, wiring, and pumps examined before power is restored or components are touched.
- Drainfield and distribution area. Look for erosion, exposed pipes, sediment deposits, standing sewage, soft soil, or damage from moving water and debris.
Most buried tanks are not automatically ruined by a flood. The EPA notes that tanks and pump chambers can fill with silt and debris even when the tank itself remains intact. After the soil is no longer saturated, professional pumping or cleaning may be needed to remove that material. The inspection should determine what entered the system and whether the drainfield can still accept wastewater.
Which warning signs need prompt septic service?
Flooding can temporarily slow a system, but persistent or worsening symptoms need a diagnosis. Do not assume that a pump-out will fix every problem.
- Several sinks, tubs, or toilets drain slowly after household use resumes
- Toilets gurgle or fail to clear normally
- A floor drain overflows or sewage backs up indoors
- A high-water or pump alarm remains active
- Sewage, gray water, or strong odor appears over the tank or drainfield
- The tank, riser, lid, or nearby soil has shifted or settled
- Pipes, wires, or system parts have become exposed
- Wet or soft ground remains over the drainfield after surrounding areas have drained
Keep people away from any sewage at the surface. Do not remove a tank lid to investigate, reach into a pump chamber, or handle wet electrical controls. Septic tanks can contain dangerous gases, and flood damage can make access covers and nearby soil unstable.
What if the home also uses a private well?
Treat the well and septic system as separate flood recovery tasks. Do not assume clear well water is safe. Floodwater can carry sewage and other contaminants into a damaged or submerged well.
The EPA advises homeowners not to drink well water after a flood until it has been tested and to contact the local health department. Use bottled water or another supply recommended by public health officials for drinking, preparing food, brushing teeth, and other uses until the well is cleared for service.
Do not try to solve a suspected well problem by sending large amounts of water through the septic system. Well disinfection, flushing, sampling, and septic recovery should follow the instructions of the local health or environmental authority for your property.
How should you clean up sewage after a flood?
A sewage backup needs careful cleanup because the water may contain disease-causing organisms. Avoid skin contact and keep anyone without suitable protective equipment out of the area. Do not use electrical equipment while standing in water, and do not enter a room if damaged wiring or energized equipment may be present.
Follow current instructions from your local health department for removing contaminated materials, cleaning hard surfaces, drying the building, and using disinfectants. Never mix bleach with ammonia, acids, or other cleaners. If business chemicals, fuel, pesticides, or other hazardous materials may have entered the septic wastewater, tell the cleanup and septic professionals before they begin work.
How can you protect the property during recovery?
Keep all vehicles and machinery away from the tank and drainfield while the soil is wet. Mark the septic area so cleanup crews do not park, store debris, or create a travel path over it. Do not dig trenches, place fill, or reshape the drainfield without direction from the local permitting authority and a qualified professional.
After the soil becomes stable, document erosion, exposed components, settled areas, and repairs with dated photos. Replace soil and grass only as directed when septic parts or final grading may need inspection. Save the inspection report, pumping record, repair invoice, and permit documents with the home's septic records.
If flooding came from a hurricane or tropical storm, compare the damage with the steps in our septic system hurricane preparation guide. It can help you update the property plan before the next storm without changing the approved recovery work.
Who should you contact about a flooded septic system in Concord?
Contact the local health or environmental department for property-specific guidance, permit requirements, and any flood recovery advisories. Arrange a septic inspection if the system backed up, electrical parts were submerged, components shifted, silt entered a tank or chamber, or the drainfield will not accept normal flow after the ground drains.
Describe what flooded, how high the water reached, whether sewage backed up, whether the system has a pump or alarm, and whether any part moved or became exposed. That information helps the provider plan a safer inspection.
For help arranging septic service after the soil is no longer flooded or saturated, Call (980) 351-2552. Reduce water use until the system has been checked, and do not ask for pumping while high groundwater is still pressing against the tank.