MPCA logo

Minnesota Pollution Control Agency

Search, View and Navigation

Beta - Dynamic

MPCA e-Services

tinyURL : 4k3p8ph | ID : 5063Home   >   About MPCA   >   News and Media   >   MPCA News Releases

main content

December 05 2013 14:37

Keep Jack Frost out of septic systems as cold temperatures arrive

Contact: Dan Olson, 218-846-8108

St. Paul, Minn. — Just as frost can cause problems with underground pipes in cities, it can also impact pipes and other parts of septic systems that are used to treat and disperse sewage. Cold temperatures combined with lack of snow in some areas may spell problems for some Minnesota residents who rely on subsurface sewage treatment systems or septic systems.

 “Snow helps to insulate septic systems and keep them from freezing,” said Dan Olson, public information officer with the Minnesota Pollution Control Agency (MPCA). While much of Minnesota has received snow already this season, some areas still have sparse snow cover.

With cold temperatures spreading across much of Minnesota, there are several things homeowners can do to prevent their septic system from freezing:

  • Place a layer of vegetative insulation eight to 12 inches thick over the pipes, tank and soil treatment system to provide extra insulation. This insulation can be straw, leaves or other loose material that will stay in place and not become compacted. Spread out several bales of straw on top of the septic tank and drainfield area- and try to extend out a few feet around the outside of the tank(s). Insulation is particularly important for new systems installed so late in the year that vegetative cover has not been fully established.
  • If you're worried that your system is starting to freeze, use water—the warmer the better—as regularly as possible. Spread out your laundry schedule so you run one warm/hot load a day. Use the dishwasher and take hot baths. However, DO NOT leave water running all the time, as this will hydraulically overload the septic system.
  • Leaving for an extended period? Have someone use warm water in your home regularly while you are gone, or have your septic tank pumped out before you leave. If a shallow tank is left full for several winter months, the sewage will become very cold and can freeze.
  • Fix any leaky plumbing fixtures or appliances in your home. This will help prevent freezing problems and help your system perform better all year long.
  • If you have appliances that generate very low flows, such as high-efficiency furnaces, you can put heat tape in the pipe, and have someone run warm water for a while you are gone. Alternatively, install a small condensate pump that holds and discharges two gallons per cycle.
  • Keep all vehicles, animal and human traffic off the system. This is a good rule to follow all year long as compacted snow and soils cause frost to go down deeper and faster. Pay special attention to the area between the house and the septic tank.
  • Make sure all risers, inspection pipes and manholes have covers. Making sure lids are closed tight and adding insulation is a good idea. Insulation may be added during construction particularly if the top of the septic tank is within two feet of the surface.
  • Keep an eye on your system. If any seeping or ponding occurs, contact a septic system professional to help determine the cause and remedy.
  • Add more insulation to your system. This could include replacing pipe with insulated pipe, installing expanded foam panels over the septic tank, or adding more soil cover.

A common cause of freeze-ups is pipes that are not installed with the proper pitch or that have settled, resulting in dips in the line. Where a dip or flat spot occurs, sewage can collect and freeze. Pump lines can develop a dip right next to or above the septic tank as a result of soil backfilled during tank installation settling.

If your septic system freezes, call a septic system professional. The MPCA website includes a search tool for finding certified installers, maintainers, or service providers in your area. (Search the Internet for "MPCA SSTS licensed business search”. In addition to checking your local area, also check surrounding counties since licensed businesses frequently work in multiple counties.

If it’s not feasible to correct a problem, the only option is using the septic tank as a holding tank until the system thaws naturally. Have a septic maintainer empty the tank when it is nearly full. To minimize pumping costs you can reduce water use by limiting the number of toilet flushes, taking short showers, laundering at a laundromat, eating prepared meals, using paper plates and disposable utensils and/or using the dishwasher only at full capacity.

There are some things residents should never do to try to fix a frozen system:

  • Do not introduce antifreeze, salt or a septic system additive into the system.
  • Do not pump sewage onto the ground surface.
  • Do not start a fire over the system to attempt to thaw it out.
  • Do not run water continually to try to thaw the system. This can overload the system.

More information is available at

additional content

Connect with us