Pipes freeze when water in them drops below 32 degrees, which happens fastest in uninsulated lines running through unconditioned space — exterior walls, attics, crawlspaces, garages, and unheated additions. They burst not from the ice itself but from pressure trapped between the ice blockage and a closed faucet.
Why Pipes Actually Burst
Worth understanding, because it explains the prevention. Water expands as it freezes, but the break rarely happens at the ice. Instead, the expanding ice pushes water ahead of it toward a closed faucet, and pressure builds in that trapped section until the pipe fails — often several feet downstream of the frozen spot. That is why opening a faucet to relieve pressure is genuinely effective.
The Common Causes
- Pipes in unconditioned space. Exterior walls, attics, crawlspaces, garages, and unheated additions. In Albuquerque and Santa Fe these are where nearly every freeze failure happens.
- Missing or inadequate pipe insulation on those runs.
- Rapid overnight temperature drops. New Mexico’s 40-degree daily swings mean a mild afternoon can be followed by a hard freeze — homeowners get caught because the day did not feel cold.
- Unheated or under-heated spaces — a vacant house, a thermostat set too low while traveling, or a heating failure.
- Exterior hose bibs with hoses still attached, which trap water at the valve.
- Gaps and air leaks in exterior walls and rim joists that let cold air reach pipes directly.
- Wind exposure, which drives cold through gaps far faster than still air.
Why New Mexico Gets Caught
Our winters are mild on average and sharp at the extremes, which produces two problems. Homes here are often built with less freeze protection than colder climates demand — pipes in exterior walls, minimal insulation on attic runs. And homeowners are not in the habit of preparing, because most nights do not require it. Then a cold snap arrives and the whole metro floods with burst pipe calls at once.
Prevention
Insulate exposed pipes, disconnect hoses, seal air leaks, keep the house heated even when away, and let a faucet drip during hard freezes. See frozen pipe repair and consider insulation improvements.
