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Septic Systems And Winter Weather: What You Need To Know

by Erik Evans

Rough winter weather can pose a variety of challenges to the average septic system. Knowing how to maintain and manage your septic tank and soil treatment components throughout the winter can help your system last longer and reduce the possibility of expensive repairs. Here's what you should know about the effects of winter on your septic tank system:

An Unlikely Insulator

Believe it or not, snow cover actually provides an insulating layer for septic tanks and drainfields. Uncompacted snow helps the ground retain much of the heat energy that comes from natural geothermal activity as well as the breakdown of sewage in the septic tank itself.

However, snow can lose much of its insulating capability once it's compacted. This loss of insulation allows frost to penetrate deeper into the ground and dissipate the natural heat. This makes it more likely for portions the septic system to freeze.

To prevent this from happening, you should anything that could create compacted snow off of areas where your septic system components lay. That includes vehicles (cars, ATVs and snowmobiles), livestock and even foot traffic.

The Trouble with Snow Runoff

The spring thaw can bring many problems to a typical septic system. As the snow begins to melt, the runoff can make its way into the drainfield instead of draining off elsewhere. This unexpected influx of water competes with the natural influx of water arriving from your house.

The end result is a temporary high water table that completely saturates the drainfield, which can easily interfere with how your waste water moves through the septic system. Symptoms usually include slow drainage and wastewater backup through toilets and basement drains.

There are several short-term solutions you can use to mitigate the effects of snow runoff on your property's septic system:

  • Limit water usage throughout your household. That includes limiting the amount of water used for showers, laundry, dishwashing and toilet flushing.
  • Inspect every indoor and outdoor faucet for signs of leaks. Even a minor leak can slowly add stress to your septic system.
  • Don't allow water from your home's basement sump pump to drain into your septic system.

The long-term solution to snow and rainwater runoff involves designing groundwater paths that help prevent flooding and septic field failures. You should also consider the role your home's roof and gutter system plays in handling snowmelt and rainfall runoff.

What to Do If Your System Freezes

If you're already confronted with a frozen septic system, there are two ways you can handle the problem. You can have your septic tank specialist attempt to unfreeze the system piping through the use of high-pressure jets or steam. This option might not be feasible if the specialist detects a leak or if the entire drainfield has frozen over.

Your only other option is to simply wait it out until the spring thaw. Your septic system specialist may have to pump out all of the excess water and effluent that's accumulated within the system as it thaws, which could cost you additional time and money.

Long-term solutions for preventing septic freeze-ups include adding just enough mulch to provide an insulating effect during the winter, but not so much that it prevents soil moisture from evaporating properly. Most experts recommend adding 8 to 10 inches over the drainfield, pipes and the septic tank itself. You can also invest in insulation for your system's pipes, along with the addition of expanded foam insulation over the tanks.

What Not to Do

What you shouldn't do is attempt to unthaw the septic system yourself. Starting a fire over the drainfield will just scorch your lawn and cause your neighbors to panic. Pumping antifreeze or salt into the septic system will also ruin it in short order. Running water over the drainfield in hopes of unthawing it simply adds more water to the mix, which can make your drainfield problems worse.