A burst frozen pipe can dump hundreds of gallons of water into your home in minutes. The average insurance claim from frozen pipe damage is $15,000. Prevention costs almost nothing. This guide covers both — so you're ready before the cold snap hits and equipped if pipes do freeze.
Why Pipes Freeze and Burst
Water expands when it freezes. In a sealed pipe, this expansion creates pressure of up to 2,000 PSI — far exceeding any pipe's burst pressure. The pipe doesn't always burst at the frozen section; it usually bursts between the frozen blockage and a closed faucet where pressure builds. This is why turning on a trickle of water is an effective preventive measure.
Pipes most at risk: those in exterior walls, unheated basements or crawl spaces, garages, and any section exposed to outside air. Pipes freeze most commonly when temperatures drop below 20°F for 6+ hours.
Prevention: Before the Cold Snap
Insulate Vulnerable Pipes
Foam pipe insulation sleeves ($1-$2 per foot) are the single most effective and inexpensive prevention measure. Focus on pipes in exterior walls, crawl spaces, garages, and near drafty windows. For extreme cold, heat tape (self-regulating electric heat tape, $30-$80) provides active warming for the most at-risk sections.
Seal Drafts Near Pipes
Cold air getting to the pipe is the problem. Seal holes, gaps, and cracks in exterior walls near pipes with spray foam or caulk. Close crawl space vents during cold periods.
Keep Heat On When Away
Never set your thermostat below 55°F when leaving for an extended period. The cost of running the heat is far less than water damage repair. Open cabinet doors under sinks on exterior walls to allow warm air to circulate around pipes.
Drip Faucets in Extreme Cold
A slow drip (one drop per second) keeps water moving and relieves pressure. Turn on both hot and cold taps slightly on any faucet connected to exposed pipes during severe cold warnings.
Disconnect Outdoor Hoses
A connected hose traps water in the outdoor faucet, which can freeze back into the wall. Disconnect and drain all garden hoses before the first freeze. If you have freeze-proof outdoor faucets, disconnecting the hose is even more important — the faucet can't drain with a hose attached.
What to Do When Pipes Freeze
How to Locate the Frozen Section
Open the affected faucet. Feel along the pipe toward exterior walls or cold areas — the pipe will feel noticeably colder at the frozen section. In some cases, frost is visible on the exterior of the pipe.
Safe Thawing Methods
- Hair dryer: Most commonly used. Safe and controllable. Start closest to the faucet and work toward the frozen section. Keep moving — don't concentrate heat in one spot.
- Heating pad wrapped around the pipe: Effective for accessible pipes. Wrap securely and turn to medium heat.
- Warm towels: Soak in hot water, wring partially, wrap around the pipe. Labor-intensive but works for accessible sections.
- Portable space heater: Effective for pipes in an enclosed area like a cabinet or crawl space. Don't leave unattended.
What NOT to Do
- Never use an open flame (torch, lighter) — fire hazard and can damage pipes
- Never use a heat gun — too much concentrated heat, melts PVC
- Don't use boiling water — thermal shock can crack pipes
If the Pipe Has Burst
If you turn on a faucet and water doesn't come out, or you open a thawed section and find a crack, shut off the main water supply immediately. A burst pipe is an emergency — call a plumber right away. Document the damage with photos for insurance.
Frozen or Burst Pipe? Call a Plumber Now.
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