Take steps now to protect your septic system from freezing
By VALERIE PRAX, University of Minnesota Extension

Common reasons systems freeze are lack of snow cover, cold temps

Low snowfall amounts can mean potential danger for your septic system. For the last few winters, we have had a pattern of sub-zero weather arriving before major snowfall. Remember last winter? We did not get significant snowfall until March.

Common reasons septic systems freeze are a lack of snow cover and cold temperatures, combined with construction or "use" issues. These can include a waterlogged system, cold air entering the system, compacted soil or lack of plant cover. Others include irregular use of the system, leaking plumbing fixtures or a pipe that does not have the proper change of elevation.

If the soil over a pipe is compacted, the elevation of the pipe may shift, causing a loss of gravity flow. This results in water left standing in pipes, which can freeze easily. If your system has frozen, you should contact a professional sewage pumper or installer.

Here are some precautions:

• Stop mowing the grass over the drainfield in early fall. Let it grow stronger to trap more snow.

• Add a layer of mulch (8-12 inches) over the pipes, tank and soil treatment area to provide insulation. A mulch of loose hay or straw works well, as do leaves. The key is to keep it loose to form air pockets, which act as the insulators. This is particularly important if your system is new, and vegetative cover has not been well established.

• Use normal amounts of water; the warmer the better. Spread out your laundry schedule to one warm/hot load per day, year around.

• Don’t leave water running all the time to prevent freezing. A slow trickle could freeze, while a steady stream could overload the system with water.

• Don’t add antifreeze to the system.

• If you plan to be gone for more than a day or two, plan accordingly. Have someone visit and use water regularly. If you are going to be gone for an extended period (weeks or months), pumping the tank before leaving may be the best option.

• Reroute the drip water from your furnace. This slow drip can freeze in the pipes. Route this clean water into the sump or a bucket.

• Fix any leaky plumbing. The small trickles of water going into the system can freeze as thin ice layers within pipes, and eventually close them.

• Keep all vehicles (including ATVs and snowmobiles) and high-traffic people activities off the system, all year.

• Make sure all risers, inspection pipes and manholes have tight covers. Adding insulation is a good idea. Check for any cracks in the covers in the fall.

• Keep an eye on your system. If any seeping or ponding occurs, contact an onsite professional.

For more information, see the University of Minnesota Extension onsite sewage program Web site, http://septic.umn.edu, email malmq002@umn.edu or call 888-241-4528.

Prax is a water resource management educator with University of Minnesota Extension.