A pipe doesn’t burst because ice takes up more room than water — not exactly. It bursts because ice forms a plug, and the water trapped between that plug and a closed faucet has nowhere to go as pressure builds. That’s why the split is usually downstream of the ice, and why opening a faucet is the single most useful thing you can do.
After enough winters you stop being surprised. The list is short and it’s the same in every town:
Two conditions make all of these worse. Wind, which strips heat out of a crawlspace far faster than still air at the same temperature. And bare frozen ground with no snow cover, which lets frost drive much deeper than a snowy winter does — the hill towns like Sanbornton, Gilmanton, and the Northfield ridges get the worst of this.
Close and insulate crawlspace vents before the first hard freeze, and physically check them rather than assuming. Insulate and heat-tape any run you know is in a cold space — a proper heat cable with a thermostat, plugged into a circuit you haven’t disabled. Open cabinet doors under sinks on exterior walls during a cold snap so room heat can reach the pipes. Leave a pencil-width trickle running from the fixture farthest from where the water comes in, on the coldest nights; moving water is much harder to freeze and it relieves pressure if a plug does form.
And disconnect every garden hose in the fall. It takes four minutes and it prevents one of the most common and most annoying failures there is.
If a run keeps freezing every year, insulating it is a patch. The real fix is rerouting that line inside the heated envelope, or running a heat register into the space it passes through. On a converted camp that’s usually a few hundred dollars and it permanently removes the risk.
If a tap runs dry during a cold snap and you can find the frozen section:
Never use a torch or any open flame. It’s a leading cause of house fires during cold snaps, and it can boil the water inside the pipe and burst it while you’re standing there. And if the frozen section is inside a wall, if you can’t locate it, or if you see any bulge or deformation in the pipe, stop. A pipe that has already cracked releases everything at once the moment it thaws, and you want someone standing there with the shut-off in hand when that happens.
The order matters and it’s worth memorizing before you need it:
Stay out from under any ceiling that’s bulging. A sagging ceiling is holding a great deal of weight and it comes down all at once.
This surprises people every year, so it’s worth stating plainly. Homeowners policies generally cover the water damage a sudden burst causes — the drywall, the flooring, the contents — and generally do not cover the pipe itself. The New Hampshire Insurance Department publishes consumer guidance on this and it’s worth reading before you need it.
More important: most policies require that you took reasonable precautions. In practice that usually means the home was kept at a minimum interior temperature — commonly 55°F — or that the water supply was shut off if the home was vacant. If you leave a seasonal house heated rather than winterized, and the furnace fails, and the pipes freeze, the conversation with your carrier gets complicated. That’s the real argument for a low-temperature alarm: it’s about forty dollars and it’s the difference between a heat failure and a claim.
For scale: nationally, more than 20,000 frozen-pipe and winter water-damage claims were filed from 2024 through mid-2025, totaling over $628 million paid, with the average claim above $30,000.
Sources: New Hampshire Insurance Department consumer guidance on frozen pipes and water damage coverage; State Farm claims data, 2024–2025. Your policy is the authority on your coverage — read it, or ask your agent, before winter.
Water freezes at 32°F, but a pipe inside a building doesn’t freeze the moment the outside air does — what matters is how long the pipe itself stays below freezing. In practice, pipes in New Hampshire crawlspaces and exterior walls start letting go during sustained stretches in the teens and below, especially with wind and no snow cover.
On the coldest nights, yes — a pencil-width trickle from the fixture farthest from where the water enters. Moving water is much harder to freeze, and an open faucet gives pressure somewhere to go if a plug does form. It costs a few gallons and it works.
For now. But it froze for a reason and that reason hasn’t changed — it’ll freeze again on the next cold snap, and eventually one of those times it will split. Find out why that run is cold and fix it while it’s an appointment instead of an emergency.
Proper self-regulating heat cable with a thermostat, installed to the manufacturer’s instructions and plugged into a working outlet, yes. Old-style constant-wattage tape wrapped over itself, or cable that’s been on a pipe for fifteen years, no — it’s a fire risk. If yours is old, replace it before you rely on it.
Shut the water off first if it’s already going. Then tell us what you’re seeing.
Shut the water off first, then tell us what you’re seeing. We’ll tell you honestly how fast we can get there.
We reply to every request within 2 business hours.
