To thaw a frozen pipe, open the faucet it feeds, then warm the frozen section slowly with a hair dryer, a heating pad or warm towels, working from the faucet back toward the frozen spot. Never use an open flame. If you can't find or reach the frozen section, or the pipe has cracked, shut off the main water valve and call a plumber.
Reviewed by Ron Olsen, Master Plumber, certified in Washington
Why Pipes Freeze
- Pipes in unheated spaces
- Pipes in attics, crawl spaces, garages and exterior walls freeze first.
- Poor insulation
- Gaps around pipes let cold air reach them.
- Sudden hard freezes
- Homes in mild climates are often built with less pipe protection.
- Low thermostat settings
- Turning the heat down while away can let indoor pipes freeze.
How to Thaw a Pipe Safely
- Open the faucet so melting ice and water can flow out.
- Warm the pipe with a hair dryer, heating pad or warm towels, starting nearest the faucet.
- Open the cabinet doors under sinks to let warm air in.
- Keep thawing until full water pressure returns.
- Never use a torch, open flame or kerosene heater to thaw pipes.
When to Call a Plumber
Call a plumber if you can't find or reach the frozen section, if the pipe is inside a wall, if several pipes are frozen, or if a pipe has cracked. Pipes often split while frozen and only start leaking as they thaw, so keep the main valve within reach.
The repair is usually part of pipe repair & repiping, which explains what the plumber does and what affects the cost.
Freeze Risk by City
What our city pages say about freeze risk:
- Sioux Falls, SD: Very high. Long sub-zero stretches freeze pipes in exterior walls, crawl spaces and unheated basements.
- South Lake Tahoe, CA: Very high. Winter nights fall into single digits and freeze pipes in empty and drafty homes.
- Cheektowaga, NY: Very high. Long, cold, snowy winters freeze pipes in exterior walls, basements and unheated spaces.
- Missoula, MT: Very high. Long cold stretches freeze pipes in exterior walls, crawl spaces and service lines.
- Plymouth, MN: Very high. Long subzero stretches freeze pipes in exterior walls, crawl spaces and service lines.
- Anchorage, AK: Very high. Months of sub-freezing weather freeze pipes in exterior walls, crawl spaces and garages, and can freeze buried service lines.
- Portland, ME: Very high. Long, cold winters freeze pipes in exterior walls, basements and unheated spaces.
- Flagstaff, AZ: Very high. Cold nights at 7,000 feet freeze pipes in exterior walls, crawl spaces and garages.
Other Pipe Repair & Repiping Problems
Frozen Pipe Questions
How do I know if a pipe is frozen?
A faucet that gives only a trickle or no water in freezing weather is the main sign. You may also see frost on exposed pipes.
How do I prevent frozen pipes?
Insulate exposed pipes, seal drafts, keep the heat on when away, open cabinet doors on cold nights, and let faucets on exterior walls drip during hard freezes.