Cold weather can cause septic system problems

For persons new to country living, the concept of a septic system can be a bit of a mystery.

Urban dwellings are most often attached to city sewers, which seldom if ever require attention or maintenance on the part of the homeowner.

A private septic system, on the other hand, requires regular emptying and some common-sense maintenance in order to avoid unpleasant and expensive repairs, especially as winter sets in.

As temperatures fall below freezing and frost enters the ground, septic systems are vulnerable to freezing for a variety of reasons. A frozen system will, at best, stop working, leading to major inconvenience and expensive repairs. At worst, the system can back up into the home, adding health and safety risks to the expense and inconvenience of repair.

Low Temperatures Can

Freeze System

Small amounts of water can lead to big problems in cold weather, according to Gary Schluender, who owns a construction and septic tank service business in Monticello.

A high-efficiency furnace or humidifier system releases a trickle of water into the septic system pipes, which can collect in the pipes and freeze, eventually blocking the system. Leaky shower heads or toilet tanks can also contribute to this problem. Regular household water use will normally prevent this condition, as water from sinks, bathtubs, laundry and dishwashers helps keep the temperature in the septic system warm enough to prevent freezing.

Pipes freezing due to small amounts of water use are typically more of a problem in situations where homeowners are gone on vacation for an extended period in winter, or in cabins or vacation properties that see limited cold-weather occupancy.

Schluender recommends the use of straw or mulch to help insulate systems that may be at risk of freezing, though he notes that such materials need to be in place before the ground freezes to be effective.

Thawing a septic system is usually not a difficult or time-consuming project for a company like Schluender's, which has the equipment to open frozen pipes in a matter of minutes, in many cases. The problem is, if a system has frozen once, it may very well freeze again, leading to ongoing service calls and added expense.

A bend or "belly" in the pipe leading to the septic tank is often the culprit, he noted, as water will pool in that section of the pipe and will often freeze. In this situation, repairs will have to be done to the system by digging up and realigning the pipes once the frost leaves the ground in the spring.

Schluender's company has been in business in the area for 45 years, and he says that the area north of Hwy. 10, including Becker, accounts for 80% of his service calls for frozen pipes every year. Sandy soil conditions may be a factor, he said, and depth of system installations can also play a role.

He noted a spike in service calls for frozen pipes three years ago, with the number of calls down in the past two years, even with minimal snow cover. He recommends that homeowners have their septic systems cleaned every two to three years to keep the system running properly and to avoid damage to drain fields. Schluender Construction and Septic Services can be reached at (763) 295-5784.

Darrel Fiedler of Fiedler's Pumping Specialists in Rice says that insulation over the drain field, septic tank and the pipes leading to the home is one of the best ways of keeping frost out of the system. A mulch of leaves and grasses works well, as will straw bales spread out over the area. Freezing problems can often start in the drain field, he noted, and spread to the septic tank and pipes.

Fiedler also notes that warm water is very important in keeping systems working properly. Having a neighbor stop by to run cold water in sinks or flush toilets can actually add to the problem, he said, since the cold water only adds to the already cold material in the tank, making it more likely to freeze. Running a sink full of hot water, or running a dishwasher will help, since it raises the temperature inside the septic tank.

One handy thing homeowners can do, Fiedler said, is to mark the location of tank caps with a lath or wire flag, which makes it much easier for pump crews to locate the tanks when they are covered with snow in the winter months. The firm has been in the pumping business for 41 years, he noted.

Fiedler's Pumping Specialists, Inc. can be reached at (320) 743-3832.

According to information published by the Minnesota Extension Service, factors that can cause a septic system to fully or partially freeze include the following:

Lack of snow cover: Snow works as insulation material, helping to hold in heat from sewage and preventing septic tanks, pipes and drain fields from freezing. It also insulates the system from the cold surface air, preventing frost from penetrating down to the septic system. Compacted snow on top of a septic system greatly lessens the insulating effect, so vehicles, equipment and even foot traffic should always be routed around the system location.

Irregular use: If homes or vacation cabins are unoccupied for long periods of time, the lack of water and sewage entering the system does not supply sufficient heat for the system to resist freezing.

Leaking fixtures: A leaking shower head or toilet can release a thin trickle of water into the system, which can cause a build-up of ice and eventually freeze pipes. High-efficiency furnaces and humidifiers can also be a factor due to the small amounts of water they discharge into the pipes.

Improper drainage: If sewer pipes and pump lines are not installed with the proper rate of fall (insufficient change of elevation), water and sewage will not fully drain out of the system and can freeze inside the pipes.

Cold air exposure: If the outside riser cap is open, broken or cracked, cold outside air can be drawn into the system, causing the pipes and tank to freeze.

Hydraulic overload: If water is coming to the surface around the septic tank, or leaking from the side of a mound-type system, freezing is very likely as temperatures fall.

Do's And Dont's

If a septic system freezes, the best recourse is to contact a professional on-site technician who can diagnose the problem and provide an effective and safe solution. A pumper truck may be required to empty the septic tank, and specialized equipment such as steam hoses and other devices may have to be employed. The University of Minnesota Onsite Program has a website to help in locating professionals who specialize in these problems. They can be contacted at

Do not attempt to introduce antifreeze, salt or other system additives into a frozen septic system. Building a fire over a frozen system is also not a good idea, nor is continually running water an effective remedy. Also, never run raw sewage onto the ground in an effort to bypass a frozen system.

Preventative Measures

Before cold weather arrives, a layer of up to 12 inches of mulch over the septic tank and pipes will provide effective insulation for the system. This can include hay, straw, leaves or other loose materials. Letting the grass grow longer over the system late in the summer is also an effective means of adding insulation.

Use more and warmer water when possible. Plan laundry and dishwasher use to spread out the time between applications. Fix any leaking connections before cold weather sets in, and consider adding heating tape to vulnerable pipes. Keep vehicles and foot traffic away from buried pipes and septic tanks, and check all risers, inspection covers and manhole covers to ensure access to cold air is blocked.

If leaving home for an extended period, consider having the septic tank pumped out to prevent freezing of the effluent inside. Another option is to have someone come into the home and use sufficient amounts of warm water to make the system function properly.

Other measures include replacing system pipes with insulated versions, adding Styrofoam over the septic tank, and adding more soil cover over the tank and pipes.

For more information, contact the Minnesota Extension Service at (800) 322-8642.


Sherburne County Citizen

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