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Effects of Flooding on Wells and Septic Systems

By December 23, 2013News

Wells: Floods, earthquakes and other disasters can damage or contaminate wells. If the well is not tightly capped or properly grouted, sediment and flood water could enter the well and cause contamination. Dug wells, bored wells, and other wells less than 50 feet deep are more likely to be contaminated, even if damage is not apparent.

Treating a Well: If extensive flooding has occurred or you suspect that the well may be contaminated, DON’T drink the water. Use a safe water supply like bottled or treated water. Contact your local, state, or tribal health department for specific advice on wells and testing.

Working on a well after a natural disaster can be hazardous. Disasters such as earthquakes, fires and floods can damage well piping and electrical systems. Unless you are highly skilled, electrical repairs are best conducted by a qualified electrician or well contractor.

Follow the guidance for your type of well:

IMPORTANT: Fuel and other chemical releases and spills are common during flood events. If your water smells like fuel or has a chemical odor or if you live in an area where the potential for a release of fuels, pesticides, or other hazardous chemicals is high, contact your local health department for specific advice. Until you know the water is safe, use bottled water or some other safe supply of water.

Power Outages and a Private Well

Septic Systems:   This website has information on what to do if your septic system is in a flooded area, if it is a business that disposes of chemicals, if repair work is needed to wait until the ground is no longer saturated to prevent compaction which could lead to system failure, when to avoid using the system and other useful advice.

Ohio Department of Health Fact Sheet- What to do when your Household Sewage System is Flooded

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.