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Sewage Treatment Systems in an Emergency

Sewage Treatment Systems in an Emergency

The information provided here is guidance for proper management of your Sewage Treatment System (septic system) once it has experienced either a power failure or flood event.  Remember to use the print button at bottom of page and not the browser's print function.


Sewage Treatment Systems During a Power Outage

Electrical power outages may affect the operation of your home sewage treatment system.  Sewage treatment systems operate either by gravity, or involve the use of pumps and valves that require electricity.  You will need to determine which type of system serves your home.

A gravity collection system feeding into a septic tank and gravity distribution into leaching trenches or the soil absorption area will continue to operate properly and you will be able to continue using your system.   You may use buckets of water (from a pond, stream or other similar source) to manually flush the toilet.

If your system contains components that require electricity to operate, the wastewater will collect in the septic tank, treatment unit or dosing tank during the electrical outage and will have to be treated and dispersed when electrical service resumes. Such components include:

  1. Aerobic treatment units and recirculating media filters
  2. Pump chambers to leaching (soil absorption) trenches
  3. Sand filters
  4. Dosing or flow equalization tanks
  5. Low pressure distribution
  6. Subsurface drip distribution

What can I do while the power is out?

Limit water usage to essentials such as toilet flushing and hand washing. Laundry, bathing, showers, and dishwashing should be minimized or eliminated during the power outage. Don't let the water run while brushing teeth, shaving or rinsing dishes.  Don't flush the toilet each time it's used for liquid waste.

The septic tank can hold about one-day's supply of waste. Once the tank is filled, additional waste can back up into your home.

Stop all water use if electrical outage is extended or the plumbing begins to drain slowly. Slow-draining plumbing may indicate that the reserve capacity in the tank is exceeded and the system is full.

If the system has a pump, turn off the pump at the control panel. Effluent (liquid sewage from the septic tank) will continue to build up in the pump chamber until it resumes operation.

CAUTION: Do not enter the pump chamber. Gases inside pump chambers are poisonous and the lack of oxygen can be fatal. Always turn off the power supply at the circuit breaker, and unplug all power cords before handling the pump or floats to prevent electric shock. The service or repair of pumps and other electrical equipment must be done by an experienced person.


What should I do once power is restored?

Contact your service provider or a licensed electrician if you are unsure or uncomfortable working with the components.  Your service provider will plug in any electrical equipment that was unplugged during the outage.  Always be careful when working with electrical components to prevent shock. 


If you have an operation manual for your system, refer to the manual for directions on restarting your system.


If your system is demand dosed (waste is pumped out to a treatment unit or soil as the tank becomes full), the pumping system can be manually operated to disperse the stored wastewater to the soil absorption field (leaching trenches). Manually operating the dosing system may be necessary to avoid overloading your soil absorption system following the first dose after the restoration of power.  Your system can be dosed manually by:

  • When the power is restored, turn the pump 'on' for 2 minutes and 'off' for 4 – 6 hours. You are now "dosing" the right amount of effluent into the drainfield over a given period of time. If there was little water use during the power outage, the pump may automatically turn off during the first manual dosing.
  • Conserve water and continue the 2-minute pumping every 4 – 6 hours until the pump turns itself off.

If your system is time dosed, allow the system to continue to operate normally until the water level reduced in the system. A pump system with a timer controls the number of times the pump starts and stops. It manages how much effluent (liquid sewage from the septic tank) goes into the soil absorption field (leaching trenches) in a 24-hour time period. Timers make sure that the soil absorption field only gets as much effluent as it was designed to handle. The timer system will eventually take care of itself once the power is restored. If the power has been off for awhile, the timer will be behind. In order to let your timer catch up, continue to conserve water for an additional day or more.


System components that require electricity are usually equipped with a high water alarm. This alarm may sound when the power is restored based on your water usage during the power outage. You can silence the alarm if it has a silence switch option. If the alarm remains activated more than 24 hours, contact your service provider.

Sewage Treatment Systems During a Flood

Heavy storms can cause flooding over portions of your sewage treatment system.  This factsheet is designed to provide information to assist homeowners who want to prepare for a possible flood and those who have experienced a flood event.


What can I do if I am in a flood prone area well in advance of a flood?


Have a licensed plumber install a backflow preventer on the building sewer so sewage cannot backup into your home during a flood. A backflow preventer is recommended as there is some concern a simple check valve may not close properly and sewage may back-up into the home. Make sure all inspection caps are in place. Threaded caps can be installed and the pipes can be cut flush with the ground.


What can I do immediately prior to a flooding event?


If the building sewer has a backflow preventer, nothing further needs to be done.

If the backflow preventer is a manual valve, ensure it is shut.

It may be desirable to pump the tank to remove the sewage. Tank pumping immediately prior to flooding is not mandatory. If pumped, some sewage solids will remain in the tank and could mix with any floodwaters that enter the tank. It may be advantageous to block any lower level drains in the dwelling to prevent back up.

Make plans to minimize water use or flushing of toilets during the actual flooding event.


What should I do during the flood if the system is covered with water?


Do not use the system. Turn off water softeners to prevent them from regeneration.

Turn off the power to all the system’s electric devices (pumps, alarms, etc.).

If you are using water from a flooded well, it may be contaminated. Contact a well professional or your county about a water test.


Once the flood waters receded, when can I use my system again?


Allow the soil to adequately dry to allow sewage to be absorbed and not back-up. This may take several weeks. You should try to conserve water until the system is completely dry.

All tanks should be checked to see if they contain floodwaters. If so, the tanks should be pumped to keep the silt particles from entering the soil system.

Effluent screens (if any) should be cleaned.

The electrical system (if any) should be inspected. This includes electrical connections, pumps, alarms, etc.

If your system has a pretreatment component, you should check with your licensed service provider before operation.

Any obvious damage should be repaired. All tank maintenance hole openings must be immediately secured, repaired, or replaced if the covers have been shifted, moved or lost in the flood.


How do I know if my system is damaged?


Signs of damage include: settling of soil over the tank or soil absorption system and/or the inability of the system to accept wastewater (indicated by sewage back-up or surfacing on the ground). If you observe either of the above after flood waters recede, contact your local health department

What should I do if sewage backs up into my home?


The Ohio Department of Health has developed a factsheet titled: When Sewage Backs Up Into Your Home.  The factsheet addresses the proper steps to consider while cleaning up after a sewage backup.

What concerns are there with home clean-up activities and my septic system?


The home cleaning process will likely result in the discharge of high amounts of disinfectants and cleaners into the septic tank. It is best to pump the tanks (a second time if floodwaters were previously pumped) to avoid discharging of these chemicals into the soil absorption component of the septic system.

Do not dump floodwaters that have entered the house into a plumbing fixture which discharges into the STS.

Do not drive vehicles and equipment over the system during clean-up or restoration activities.

Do not set dumpsters or building materials over the system. Fence-off the system to protect it.


What else should I look for after the flood?

Inspect the vegetation over your septic tank and soil absorption field.

Repair erosion damage and sod or reseed areas as necessary to provide proper cover.


What septic system work can I do myself?

Due to the many hazards in working with septic systems (disease transmission, poisonous gasses, and electrical shock) it is strongly recommended that all septic system work be conducted by a professional licensed as an STS installer or service provider.  Contact your local health department for a list of these individuals.  A licensed electrician should be contacted for any electrical work.

If these professionals have determined there is no damage to your system, a homeowner may re-sod or re-seed a damaged area.