According to many septic system professionals, a winter of cold temperatures and little snow can cause freezing of onsite systems.

Even in a normal Minnesota winter, freezing can occasionally be a problem. Identifying and correcting a potential freezing problem is far easier than dealing with a frozen system. Here are a few common causes of onsite system freeze‐ups.

• Lack of snow cover – snow acts as a insulating blanket over the septic system.
• Compacted snow – will not insulate as well as uncompacted snow.
• Lack of plant cover – this often occurs with the instillation of a new septic in fall. A vegetative cover (grass) insulates the system and hold snow.
• Irregular use of the system – When homes or cabins are unoccupied for long weekends no warm sewage is entering the system to help maintain temperatures above freezing.
• Leaking plumbing fixtures and furnace drips – the slow moving water can freeze in sewer empty pipes that freeze over time.
• Cold air entering the system – broken and uncapped riser pipes and manhole covers and allow cold air to enter the system.
• What should you do if you septic system freezes – Contact a septic system professional. Unless the cause of the freezing is corrected, the system will refreeze next cold winter day. There are many wrong ideas about how to address a frozen septic system: Do NOT add antifreeze, salt or septic additives. Do NOT pump sewage onto the ground surface. Do NOT start a fire over the system Do NOT run water continually to try to unfreeze the system.

What should you do if you septic system freezes. Contact a septic system professional. Unless the cause of the freezing is corrected, the system will refreeze next cold winter day. There are many wrong ideas about how to address a frozen septic system:

• Do NOT add antifreeze, salt or septic additives.
• Do NOT pump sewage onto the ground surface.
• Do NOT start a fire over the system
• Do NOT run water continually to try to unfreeze the system.

To learn what you can do to prevent your septic system from freezing see the University of Minnesota’s Freezing Problems & Septic Systems fact sheet.