Protect your septic system from freezing

By Valerie Prax

University of Minnesota

Extension Service

Here we go again - a winter with little snow cover. That means potential danger for your septic system. Unfortunately, the sparse snowfall in Minnesota this year will probably cause problems again, says Valerie Prax, a Regional Educator with the University of Minnesota Extension Service.

The most common reason 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's not installed with 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 who can help determine the cause of the problem and offer solutions.

The U of M Onsite Sewage Program Web site at http://septic.umn.edu/homeowner/index.html has detailed information on septic system freezing problems. It can also help you locate a professional in your area.

There are many things you can do to reduce the chances of your system freezing this winter. Here are some precautions if you think you may have a problem.

• 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, a pattern that should be followed year around. Do not leave water running all the time, this will hydraulically overload the system. Do not 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.

• Fix any leaky plumbing in your home. The small trickles of water going into the system can freeze as thin ice layers within pipes, and eventually close them. If you have a high-efficiency furnace, collect the water in a large container, emptying onto the ground periodically. This does not need to go into your septic system - it is clean water.

• Keep all types of vehicles - including ATVs and snowmobiles - and high-traffic people activities off the system. This is a good rule to follow all year. Mound systems are not four-wheeler jumps!

• Make sure all risers, inspection pipes and manholes have covers. Adding insulation is a good idea.

• Keep an eye on your system. If any seeping or ponding occurs, contact an onsite professional to help determine the cause and remedy.

For more information, check the Web site or call a member of the University of Minnesota Extension Service Onsite Sewage Treatment Program Team: Laurie Brown (Cloquet), 888-241-0724, brow1198@umn.edu ; Valerie Prax (Mora), 888-241-4528, malmq002@umn.edu ; or Doug Malchow (Rochester), 507-280-5575, malch002@umn.edu .