How to Clear a Frozen Sewer Pipe

Frozen sewer pipes can be cleared with hot water.

Homeowners that leave their home unattended and unheated during freezing weather may return to find that their sewer pipe has frozen. If the pipe is located in a hard to reach spot or close to a gas line, then you should probably call a plumber to clear it for you. But if you can easily access the frozen pipe, just apply heat to defrost it and save some money on the plumbing service.

Things You'll Need

• Bucket
• Hot water
• Heavy cloth
• Electric heater
• Hair dryer

Instructions

1. Look for cracks in the pipe. Freezing water expands and can crack pipes or fittings. If you find cracks in the pipe, you must replace it. You may want a professional plumber to replace the pipe for you.

2. Open all the faucets in the house. This is very important. Eventually in this process you will heat the frozen pipe. This will create steam and pressure, which may cause the pipe to burst, unless you open all the faucets in your house to let the steam and pressure escape.

3. Fill a bucket with hot water and put the heavy cloths in it. Wring the cloths out to get rid of excess water. Then wrap them around the frozen pipe.

4. Reheat the used cloths with more hot water as they begin to chill and wrap them around the frozen pipe again.

5. Mop up the water that drains off the pipe, or set buckets out to catch the water.

6. Set up an electric space heater to heat the room containing the frozen pipe, careful to avoid contact between the heater or its wires and the water dripping from the pipe.

7. Hold a hair dryer up to the pipe and slowly move it up and down the length of the frozen section. Keep the hair dryer moving to avoid concentrating too much heat at one point on the pipe. Make sure to stand on dry ground to avoid the risk of electrical shock.

8. Listen for a crackling sound. This means that the ice within the pipe is breaking and melting, and the sewer pipe is clearing. Water trickling out of the open faucet will also let you know that the pipe has cleared.

9. Repeat Steps 3, 4 and 7 until water runs freely through all faucets in your home and the sewer pipe no longer feels frozen when you touch it.

10. Turn the water off, and check around the sewer pipe for leaks. If you find any, then you may at that point need to call a plumber to repair the pipe.

Tips & Warnings

• Do not try to heat the pipe too quickly or the sudden heat might cause the ice to expand and burst the pipe.

• Do not use any direct heating method if the frozen pipe is next to a gas line. Call a professional plumber in this instance.

References

• Plumbing Basics: Plumbing Pipe Problems
• Chest of Books: Thawing Out Frozen Pipes
• My Great Home: Frozen Pipes