Freezing Temps and an Overflowing Toilet

Frozen drainpipes may cause waste water to back up into the toilet.

Freezing temperatures may create problems with your house’s plumbing, freezing the water in the water supply or drainpipes. Frozen water in the pipes may form clogs that cause the plumbing fixture to overflow with waste water, or they may burst the pipe and lead to flooding in or near your house.

Vent Pipes

Every plumbing fixture in your house connects to a vent pipe, although not necessarily directly to the vent pipe. Instead, the drain line that connects to your toilet through the bathroom floor connects to a larger drainpipe called a branch pipe. A plumbing vent pipe connects to the branch pipe and then runs straight up and through the house’s roof. Because the vent pipes are exposed to the outside, when the temperatures drop below freezing the warm and moist air in the pipes may freeze near the pipe’s opening. You must climb onto your house’s roof if you suspect ice is clogging the vent pipe, which can be treacherous in freezing temperatures since the roof may be covered in ice. Pouring hot water down the vent pipes will break apart the ice in the pipe. Wrapping insulation or heat tape around the pipe inside your house’s attic should prevent ice forming in the vent pipe again.

Drainpipe

If your toilet’s drainpipe runs through an unfinished portion of your house, the water in the pipe may freeze. With an ice blockage in the drainpipe, the water backs up until it comes flowing up through the toilet and the toilet overflows. Examine where the toilet’s drainpipe runs and either wrap insulation around the pipe or insulate the spaces where the pipe resides.

Larger Pipes

Because the toilet’s drainpipe connects to a branch pipe, and the branch pipe connects to the sewer drainpipe, ice may form in either of the larger pipes and cause a backflow of waste water that may lead to the toilet overflowing. The toilet’s drainpipe sits lower in the floor than most other plumbing fixture’s drains, except for shower or floor drains, meaning a backup in the pipes would manifest itself through the toilet before other nearby plumbing fixtures. If you are able to insulated the larger drainpipes or heat them with a hairdryer, you may remove the ice clogs. Otherwise, you must call a plumber for help.

Sewer or Septic Tank

The overflowing toilet may be caused by ice forming in the sewer or septic tank, depending on which your house’s plumbing hooks up to. If you have a septic tank, you must contact the service you use to drain the tank for assistance in removing the ice blockage. If your plumbing system hooks up to a municipal sewer system, contact the city or county for assistance.

References

• American Red Cross: Preventing and Thawing Frozen Pipes
• Smart Plumbers and Rooters: Drain Cleaning
• South Dakota State University: Extension Specialist Offers Information for Dealing with Frozen Plumbing Vents