Winter plumbing
How to winterize your plumbing
Updated · Editorial team; not yet technically reviewed
Short answer
For a home you're living in, winterizing means protecting the pipes the heat doesn't reach: shut off and drain outdoor faucets, blow out irrigation lines, insulate pipes in crawl spaces, garages and exterior walls, and keep the heat on. A vacant home goes further: the water is shut off, every line is drained, and traps get non-toxic antifreeze.
Checklist for a home you're living in
Outdoor faucets
Disconnect hoses. If there's an inside shutoff for the hose bib, close it and open the outside faucet to drain. See outdoor faucet repair for frost-free replacements.
Irrigation
Shut off the irrigation supply and have the lines blown out, and protect the backflow device, which is often the first thing to crack.
Exposed pipes
Foam pipe insulation in crawl spaces, unheated garages and attics; heat cable listed for the purpose on pipes that froze before.
Air leaks
Seal gaps where pipes pass through exterior walls and rim joists. Cold drafts freeze pipes even in heated houses.
Know the shutoff
Find and test the main shutoff before you need it.
On the coldest nights
- Keep the thermostat at a steady setting day and night rather than a deep setback.
- Open cabinet doors under sinks on outside walls so room heat reaches the pipes.
- Let a faucet on an exterior wall drip slightly; moving water and released pressure make a split less likely.
- Keep the garage door closed if water lines run through it.
Winterizing a vacant or seasonal home
A house that will sit empty and unheated, or heated on a minimal setting with no one checking it, needs a full drain-down. It's usually done by a plumber because missing one low spot can still mean a split pipe.
Shut off the water
At the main valve, or at the curb stop if the utility allows.
Drain the system
Open every faucet, flush toilets, and drain the water heater (with power or gas off first). Low-point drains and compressed air clear what gravity misses.
Protect traps
Pour plumbing antifreeze (not automotive antifreeze) into sink, tub and floor drain traps and toilet bowls so sewer gas stays out.
Label and document
Tag the main valve and water heater so whoever opens the house knows the system is drained.
Opening the house again
Close the drains and faucets, refill slowly with a faucet open to let air out, then refill the water heater completely before turning its power or gas back on. Walk every room and the crawl space looking for drips once the system is pressurized.
Common questions
What temperature should I keep a house at to stop pipes freezing?
Many plumbers and insurers suggest not setting the heat below the mid-50s °F while away, but pipes in poorly insulated spots can freeze even then. The thermostat setting matters less than how cold the pipe's location gets.
General information; codes vary by location. See our editorial standards.