How to Thaw Frozen Pipes Safely

Locating the Frozen Section

When a faucet produces only a trickle or no water during freezing weather, a pipe has likely frozen. Check exposed pipes in unheated areas first — crawl spaces, attics, garages, and exterior walls are the most common locations. Look for frost on the outside of the pipe or a slight bulge in the pipe wall. If you can feel the pipe, frozen sections feel significantly colder than unfrozen sections. With plastic pipes, you may see the pipe slightly expanding at the frozen area.

Safe Thawing Methods

The safest way to thaw a frozen pipe is with gentle, even heat applied from the faucet end toward the frozen section. Open the affected faucet first so melting water and steam can escape. Use a hair dryer, heat lamp, or portable space heater directed at the frozen section. You can also wrap the pipe with towels soaked in hot water, replacing them as they cool. Electric pipe heating cables or heat tape can be wrapped around the pipe for gradual, controlled thawing.

Methods to Avoid

Never use an open flame (propane torch, lighter, candle) to thaw frozen pipes — this creates a fire hazard, can cause steam explosions inside the pipe, and can melt plastic pipes or unsolder copper joints. Do not use a heat gun on high settings too close to the pipe, as localized overheating causes the same problems. If the frozen pipe is behind a finished wall, open the wall cavity or use a radiant heat source placed several feet from the wall — do not attempt to apply heat through drywall with a torch.

After Thawing

Once water begins flowing, keep the faucet open and continue applying heat until full water pressure is restored. Check the entire length of the pipe for any cracks or leaks that may have occurred when the ice expanded. Even hairline cracks can cause significant water damage once the pipe thaws. If you find a split or crack, shut off the water supply to that pipe immediately and repair or replace the damaged section before restoring full water flow.