March 24, 1997

Protect your septic system from flood damage

If you have a septic system in an area that is subject to flooding this spring, there is potential for damage to the system. However, you can take action before the flooding to minimize the damage, says Barbara Liukkonen of the University of Minnesota's Extension Service.

"When floodwaters cover your septic system, it should not be used," says Liukkonen, a U of M water quality education coordinator. "If the drainfield or ground above your septic tank floods, your individual sewage treatment system is not working."

Liukkonen adds that if your drainfield is saturated or has standing water not caused by flooding from a nearby river or lake, you may have a serious problem. Contact your county health department or planning and zoning department for an inspection.

Before flooding occurs, you can prepare to minimize the adverse effects of floodwaters on your septic system, says Liukkonen. She lists the following steps:

• Seal all possible points of entry to the system. If possible, seal the manhole and inspection ports to keep excess water out of the septic tank.



• Turn off the pump at the circuit box before the area floods. If you have a pump in the lift station of a mound system, turn off the electricity. Don't forget to turn the pump back on before you use the system again. If possible, remove the pump from the tank to prevent sediment damage.



• Waterproof all electrical connections to avoid electrical shock or damage to wiring, pumps, and the electrical system.



• Plug the sewer line where it leaves your house. This may prevent sewage backup into the house. Be sure to remove the blockage before using the system again.



• If possible, have the tank pumped a week or more before the area floods. If floodwater enters the septic tank, sludge may be suspended and flushed into the drainfield. Proper pumping will reduce the amount of solid material and scum that is available to flush into the drainfield. Be sure there is enough time after pumping for the tank to refill with effluent so the tank doesn't float when the area is flooded.

After the flood, says Liukkonen, you can help your system recover. She lists the following steps to accomplish this:

• Pump the system again as soon as possible after the flood. Be sure to pump both the tank and the lift station. This will remove silt and debris that have washed into the system.



• Be careful not to compact the drainfield area by driving or operating equipment in the area, since saturated ground is especially susceptible. Compaction reduces the capacity of your drainfield to treat wastewater and could lead to an early failure of your entire system.



• Review electrical connections for damage or wear before turning electricity back on.



• Check that the manhole cover is secure and that inspection ports have not been blocked or damaged. Check for animal damage or intrusion in the drainfield area.



• Check the vegetation over your septic tank and drainfield. Repair erosion damage; sod or reseed as necessary to provide a good plant cover.



• Inside, be sure to disinfect thoroughly if sewage backed up into the house or garage. Disease-causing organisms (pathogens) in wastewater can cause serious illness, such as dysentery, hepatitis, and other waterborne illnesses.

"Remember, if your septic system has been flooded, your well may also have been inundated," says Liukkonen. "Use an alternate water source until you can test and disinfect your water supply."

A 24-page illustrated book, Septic System Owner's Guide, is available through county offices of the Minnesota Extension Service. The book is a complete guide to the operation and maintenance of individual sewage treatment systems. The book can also be ordered from the Minnesota Extension Service Distribution Center. Cost is $4 per copy plus shipping and sales tax (where applicable). To order by credit card, call (800) 876-8636 or (612) 624-4900. Ask for item PC-6583-GMM (click here for more information).

Web,V2,V4MN,V5MN,V8MN,C4,F2,H2,H5
NAGR5471

Source: Barbara Liukkonen, (612) 625-9798
Editor: Joseph Kurtz, EDS, (612) 625-3168, pkurtz@extension.umn.edu

News Page