Mild Winter – Frozen Septic?


At the risk of grossing you out or sounding unprofessional, the word we’re hearing around the Washington County Department of Public Health and Environment these days is “poopsicle!”  It refers to frozen individual sewage treatment systems/septic systems.  When a mound septic system freezes it can leak sewage out the side of the system.  It freezes and the wastewater coming out the side forms what looks like a mini-glacier of sewage.  You will just have to trust me, my co-workers have seen it.

Why in a mild winter like we have experienced would frozen septic systems be a problem?  It’s due to the lack of snow and (occasional) cold temperatures we have been experiencing.  Based on information from the University of Minnesota Onsite Septic Treatment Program, identifying and correcting a potential freezing problem is far easier than dealing with a frozen system. Snow serves as an insulating blanket over the septic tank(s) and soil treatment area (trenches, drainfield or mound). Snow cover traps the warmth of the sewage and the geothermal heat from deep soil layers.  Lack of snow allows frost to go deeper into the ground, potentially freezing the system.  An 11 inch layer of snow is equal to 4 inches of fiberglass insulation.  As many of you know we haven’t had even an inch of snow cover for most of the winter!

One indication of a frozen system is if homeowners hear an alarm or have a pump and hear water constantly running in the pump tank. If this occurs shut off the pump and call an onsite professional. This will likely be a pumper or an installer who can help determine the cause of the problem and offer solutions.  If an onsite professional determines it is not feasible to correct the problem the only other option is to use the septic tank(s) as a holding tank until the system thaws naturally. In this situation the homeowner will need to contact a pumper who will empty out the tanks when they are full.  It is important to find the cause of the freezing problem so that it can be addressed in the spring, preventing future freeze-ups.  Preventative measures that can be made to the system include adding insulation around the tank and pipes or adding additional cover.

There are many misconceptions about how to fix a frozen onsite system.  If a septic system is frozen:

  • Do NOT add 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.

When septic systems are properly installed, and are inspected and pumped out regularly, they treat household wastewater effectively and economically.  In Washington County, homeowners are required to pump their septic tanks at least every three years unless an inspection shows that pumping is not yet necessary.

In Washington County, when you sell a home or business, a compliance inspection is required to determine if the septic system meets all current standards.  A licensed compliance inspector must be hired to determine if the system is working properly.  The system may need to be replaced if it is found to be non-compliant.

To recap, take measures to prevent a frozen system before a problem occurs, and maintain the system regularly.  Septic systems are an effective and economic way to treat household wastewater if they are properly installed and maintained. Basic maintenance includes having the septic system pumped every three years and replaced if it fails a compliance inspection. When a septic system isn’t maintained they can leak sewage into drinking water supplies, nearby lakes and rivers, or overflow into your backyard and basement (like a toilet in reverse).

For additional information or to find a septic professional call 651-430-6655 or visit The University of Minnesota Onsite Sewage Treatment Program web site is another place to go to get more information on septic systems –  Rural property owners with more than five acres can qualify for low interest loans through the Department of Agriculture to replace failing septic systems. For more information on these loans, contact Pete Young at the Washington Conservation District at 651-275-1136 or

Guest Writer: Amanda Strommer is the program manager of the septic, water resources, food/beverage/lodging /pool/campground inspection and licensing, and public health nuisance programs for Washington County Department of Public Health & Environment.  Contact her at 651-430-6655 or