Quick answer: To winterize your plumbing and prevent frozen pipes: disconnect and drain garden hoses, insulate exposed pipes, cover outdoor faucets, seal drafts near plumbing, and on freezing nights let a faucet drip and open cabinet doors under sinks. A burst frozen pipe is one of the most expensive home disasters — and almost entirely preventable with a few basic parts.
A licensed plumber’s full winterizing checklist, with the exact parts for each step.
Outdoor Faucets & Hoses (do this first)
Disconnect every garden hose — a connected hose traps water that freezes back into the spigot and splits the pipe. Add insulated faucet covers over outdoor faucets, and if you’re replacing any, frost-free spigots are the permanent fix.
Insulate Exposed Pipes
Wrap pipes in unheated areas — basement, crawlspace, garage, exterior walls — with foam pipe insulation. It’s sold by the length and slips right on. For a pipe that freezes even when insulated, add a heat cable — our heat tape guide covers the types and the safety rules.
When choosing a tube material, our rubber-versus-foam insulation comparison separates exact product ratings, pipe fit, insulation thickness and exposure requirements. It also flags why a service-temperature rating does not approve an insulation cover for a heating cable.
Seal Drafts
Cold air hitting a pipe is what freezes it. Seal gaps where pipes pass through exterior walls with caulk or foam, and keep garage doors closed if water lines run through.
On Freezing Nights
Let a faucet drip slightly (moving water resists freezing), open cabinet doors under sinks on exterior walls to let warm air in, and keep the heat at a steady temperature even when away.
Reviewing how the house is heated before winter? Our baseboard-versus-forced-air comparison separates electric heaters, boiler-fed loops and ducted systems. Use that equipment check alongside the plumbing plan here; selecting a heating type does not establish protection for every pipe.
Going Away for Winter?
Shut off the main and drain the system, or at minimum keep heat at 55°F+. Any antifreeze in a plastic system has to stay within the pipe maker’s limits; Charlotte Pipe’s limits for its PVC, CPVC and ABS pipe, including its rule that toxic ethylene glycol stays out of drinking-water systems, are in antifreeze for PVC, CPVC and ABS pipe.
A freeze alarm alerts your phone if the heat quits while you’re gone. A water leak detector or smart shutoff adds insurance against a burst. Winterizing an RV with a tankless heater? Each maker has its own drain and freeze rules; see our best RV tankless water heater guide.
If a Pipe Freezes
Keep the faucet open and warm the frozen section gently with a hair dryer, an electric heating pad or towels soaked in hot water, never an open flame (American Red Cross (redcross.org)). Keep the dryer and its cord out of the melt water. Step by step: how to thaw frozen pipes. If the pipe has already split, shut off the main first and see our emergency pipe repair guide.
Which Pipes Freeze First
Insulation is only useful where the cold actually gets in, so spend the effort in this order rather than evenly. Pipes fail where they are both exposed and unheated:
- Anything in an unheated space — crawlspace, garage, attic, unheated basement, a porch or addition on its own.
- Runs in exterior walls, especially on the north side and anywhere wind hits the wall directly. Wind matters more than people expect; it strips heat far faster than still air at the same temperature.
- Under kitchen and bathroom sinks on an outside wall — which is exactly why the advice is to leave those cabinet doors open on a hard night.
- The line to any outdoor spigot, and the spigot itself.
A pipe in the middle of a heated house is not your problem. If you only have an hour, everything above beats wrapping accessible basement pipe that was never going to freeze.
Find Your Main Shut-Off Before You Need It
The most valuable five minutes in this entire checklist, and the one nobody does. Go and find your main shut-off now, in daylight, while nothing is wrong. Then actually close it and open it again.
Two things come out of that. You learn where it is and which way it turns, so at 2am with water coming through a ceiling you are not searching with a torch. And you find out whether it still works — old gate valves seize half open, or will not reseat, and discovering that during an emergency is discovering it at the worst possible moment.
If yours is stiff, weeping, or will not shut fully, replacing it is a job for a plumber and it is worth booking before winter rather than during it. The full walkthrough is in how to shut off your water main.
FAQ
At what temperature do pipes freeze?
Water freezes at 32°F, but there is no single air temperature at which pipes freeze: how cold, for how long, wind and insulation all matter. The American Red Cross (redcross.org) names the pipes that freeze most often (outdoor hose bibs, supply pipes in unheated basements, crawl spaces, attics, garages and kitchen cabinets, and pipes on exterior walls with little insulation), so protect those before a hard freeze instead of waiting for a number.
Should I let my faucet drip in cold weather?
Yes — a slight drip on the coldest nights keeps water moving and relieves pressure, which helps prevent both freezing and bursting.
How do I winterize outdoor faucets?
Disconnect hoses, shut off the indoor valve to that line if there is one, drain the spigot, and add an insulated faucet cover.
Related: Summer plumbing checklist
Related: fix a leaking outdoor faucet.
When the thaw comes, run the other half of the seasonal routine, our spring plumbing checklist, to catch any winter damage early.
Related: if a pipe freezes anyway, here’s how to thaw a frozen pipe safely before it bursts.