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Know the Risks: Septic Freezing

Frozen Pipes

As we experience large temperature drops this time of year, now is the time to consider whether your septic system is at risk of freezing. The freezing temperatures can cause various components of your septic system to freeze up. The most at-risk parts are the pipes linking the house to the septic tank. The other components that can potentially freeze are the tank itself and the pipes leading into the leach field.

We can help you understand the risks and give you some tips to ensure your septic system runs efficiently all winter long. We’ll also give you some dos and don’ts if your system does freeze.

Understand the Risks

A common problem area is a point where the pipe from the house exits the basement wall. Snow actually provides insulation to the pipe, minimizing its exposure to harsh temperatures. If there is very little snow or if there are areas of exposed soil around the system, frost can more easily penetrate and put your system at risk.

In situations where the main sewer line experiences continuous but low flow rates of water due to dripping faucets, high-efficiency furnaces, and leaky toilets, the line can freeze where the pipe leaves the basement wall. This leaves the pipes at risk for the formation of ice dams which will eventually block the pipes.

The pipe from the septic tank to the leach field is also subject to the same problems as the pipe from the house to the tank. In addition to these problems, the lack of sloping or pipe slumping causes water or poor drainage to move slowly and cause the pipe to freeze.

Tips to Beat the Freeze

  • Fix leaking plumbing fixtures or appliances in your home.
  • Place a layer of mulch 8 to 12 inches thick over the pipes, tank, and soil treatment system to create extra insulation. You can even use leaves, hay, or other loose material that won’t compact and will stay in place. This is particularly important for new systems that were installed late in the year when vegetation didn’t get a chance to establish itself.
  • Increase and manage your water use if you suspect that your system could freeze. For example, spread out laundry and dishwasher cycles and take hot showers and baths.
  • If you’re going away for an extended period of time, arrange to have family, friends, or neighbors run the warm water in your home. Or, you could pump out your tank before leaving.

What to do if Your System Does Freeze

In the event that your septic system does freeze this winter, here’s what to do (and not do):


  • Contact a professional pumper or installer to identify the point of freezing and correct the problem.


  • Add antifreeze, salt, or additives
  • Attempt to start a fire on the ground above where the tank is located
  • Continuously run water to try to thaw frozen pipes Lay mulch after the system freezes. This will prolong thawing in the spring.

If you need assistance this winter season, at Felix Septic, our experienced technicians can help. Call (603) 945-7355 or submit a request through the form on this page.

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