Pocatello winters do not ask permission. The valley sits high, the wind comes down off the benches, and January and February routinely put overnight lows in the single digits, with colder snaps stacked on top. Inside a pipe in an exterior wall or an unheated crawl space, that is freezing weather — and frozen water expands with a force that splits copper, PVC, and fittings alike. The cruelest part is the timing: a split pipe sealed by its own ice may not leak a drop until the thaw, which is why the first mild morning after a cold snap is the busiest plumbing morning of the year. Our frozen and burst pipe repair page covers the repair side; this guide is the rest of the story.
The prevention list, before the cold sets in
Know your shut-off. Before anything else on this list matters: find your main water shut-off valve, turn it once to be sure it moves, and make sure someone else in the house knows where it is. In a burst, that valve is worth more than every other preparation combined.
Cut the outside water. Disconnect garden hoses in the fall — a connected hose traps water in the faucet and the pipe behind it — and shut the inside valve to exterior faucets, then open the outside tap to drain what is left.
Insulate the vulnerable runs. Pipes in crawl spaces, garages, and exterior walls are the freeze map of every house. Foam sleeves are cheap; heat cable on the worst runs is cheaper than one repair. The bench neighborhoods like Indian Hills, where wind drives cold hardest, and the older walls of Old Town are where this hour of work pays best.
Seal the drafts. Most frozen pipes are really an air problem: a crawl-space vent left open, a gap where a line enters, wind reaching a pipe that indoor heat never touches. Sealing those paths is unglamorous and decisive.
On the coldest nights, help the pipes. Open the cabinet doors under sinks on exterior walls so house heat reaches the pipes, and let a faucet on the vulnerable run drip a thin stream — moving water resists freezing, and the drip also relieves the pressure that does the splitting. If the house will sit empty in winter, keep the heat on and consider draining the system; an empty rental over the break is the University District's classic January disaster, as our area page notes.
The ones that fool people
Two winter situations fool homeowners every year. The first is the pipe that freezes, thaws, and seems fine — the damage was a hairline split that only weeps under pressure, soaking a wall cavity slowly for weeks. If a pipe froze hard, treat the weeks after as a watching period: look for new stains, smell for mustiness, and check the crawl space with a flashlight before you decide you were lucky. The second is the vacation freeze: the house kept at a reasonable temperature, the thermostat working — and a pipe in an exterior wall that froze anyway, because wall cavities do not read thermostats. Houses that sit empty through a January cold snap, including rentals between tenants near the university, deserve a pre-trip ritual: water off at the main if the trip is long, or a neighbor with a key and this article's prevention list.
Neither situation is rare bad luck. They are the standard ways this climate tests a house, and both are survivable with a shut-off valve you can find in the dark.
The first five minutes when one lets go
Shut the main off. That is the whole first step, and every minute of flow you prevent is damage that does not happen. Open a faucet to drain the pressure. Keep electricity away from standing water. Then call — if water is spreading through a ceiling or wall, it routes as emergency plumbing, and the call itself will walk you through anything else your situation needs. If a pipe is frozen but not burst — one dry fixture, the rest of the house fine — gentle heat on the exposed section can save it, never an open flame, and the faucet it feeds stays open while you work.
And after the repair, take the lesson the pipe just taught you: it froze exactly where your house lets winter in. Fixing the insulation and the drafts alongside the pipe is what turns a January emergency into a story you only tell once. If your pipes have already split this winter, or you want the vulnerable runs found before the next snap, call (208) 753-1090 — we will connect you with an independent local plumber who spends his winters in Pocatello crawl spaces, and knows where the cold gets in. Pocatello winters are predictable — the same single-digit nights, the same wind off the benches. Your pipes' weak spots should be just as predictable, and a fall walk-through finds them while fixing them is still cheap, in daylight, with the water calmly off and back on.