How to Unthaw a Frozen Sewer Pipe

Keep your flow going and thaw the pipes.

One issued encountered when thawing frozen plumbing pipes is access to the frozen section. Many times, sewer pipes are under the house and in crawl spaces. These tight spaces make leaving a heater impractical at the least, and unsafe at worst. Once the pipes are thawed use an ounce of prevention and cover the pipes with a heat protective foam. Prepare to crawl into the small spaces to get to the frozen pipe.

Things You'll Need

• Heat tape
• Foam pipe wrap
• Utility knife

Instructions

1. Unwrap and unroll the heat tape sections to be used. Heat tape is a long flat cord with electrical heating line running through the tape's interior. Do not plug the tape into the electrical socket yet.

2. Crawl to the frozen pipe section. Bring a metal wrench to tap on the pipes to locate the frozen section. Tap and listen for reverberation or thuds. A thud noise indicates a frozen section.

3. Wrap the heat tape around the frozen section of the pipe as well as 1 to 2 feet before and after the frozen section. Plug the heat tape's plug into a standard electrical socket. Leave the crawl space hatch open, crawl out and leave the tape to heat and thaw the pipe.

4. Crawl back to check the pipes, tapping at the frozen section and listening for the reverberation versus the thud. Once thawed, flush the toilet to run water through the pipes, flushing out the chunks of ice remaining in the pipe. Remove the heat tape and cover the length of the pipe with the protective pipe foam that is available at most home hardware stores. Use the utility knife to cut the foam.

References

• Frozen Line Solutions: Frozen Septic Tanks and Sewer Lines
• Ask Me Help Desk: Frozen Pipe Thawing