Winterizing Your Plumbing
Disconnect outdoor hoses, shut and drain hose bibbs, insulate pipe in unheated spaces, and seal air leaks near plumbing runs. For a vacant property, that is not enough: drain the system fully and add antifreeze to traps, because a thermostat setting is only as good as the power supply.
The basic autumn checklist
Most winter plumbing emergencies are preventable with a couple of hours of work in October, and the single most common cause is the simplest to fix: a garden hose left connected.
Disconnect every outdoor hose
A connected hose traps water in the bibb and the pipe behind it, which then freezes and splits inside the wall. This is the most common preventable freeze failure there is.
Shut off and drain hose bibb supply
If you have interior shutoffs for outdoor spigots, close them and open the spigot to drain the line. Frost-free bibbs still need the hose off to drain properly.
Insulate pipe in unheated spaces
Foam sleeves on any run in a crawlspace, attic, garage, or exterior wall. Pay attention to the rim joist, which is a common cold path people miss.
Seal air leaks near pipes
Caulk and foam around penetrations where cold air enters near plumbing. Wind reaching a pipe matters more than ambient temperature.
Blow out irrigation and secondary water
In any freezing climate, irrigation systems must be drained or blown out. This is a common and expensive omission in Utah, Idaho, and Colorado in particular.
Know your shutoff and service the heater
Confirm the main valve works before you need it, and have heating serviced, since a furnace failure in a hard freeze becomes a plumbing emergency within hours.
During a cold snap
When a hard freeze is forecast, a few measures cost almost nothing and prevent most failures.
- Let vulnerable fixtures drip, a pencil-thin stream from the fixture furthest along an exposed run
- Open cabinet doors under sinks on exterior walls so room heat reaches the pipes
- Keep the thermostat steady; do not use an overnight setback during a hard freeze
- Open interior doors to help heat circulate to colder rooms
- If the garage holds plumbing, keep the garage door closed
- Know where the main shutoff is, and confirm it turns
Full winterization for vacant properties
For a seasonal cabin, a beach house, or any property standing empty through winter, a thermostat setting is not winterization. It depends on continuous power and a working furnace, and the whole reason these properties fail is that one of those stops while nobody is there.
Full winterization means the system contains no water to freeze.
Shut off the water at the main
Close the main supply valve, and the meter valve if you have access.
Drain the entire system
Open every faucet, highest to lowest, and open drain valves at low points. Flush every toilet to empty the tanks.
Drain the water heater
Shut off its power or gas first, then drain the tank completely via the drain valve.
Blow out the lines
Compressed air at low pressure clears water that gravity leaves behind, particularly in horizontal runs. This is the step most amateur winterizations skip.
Add antifreeze to every trap
Non-toxic RV antifreeze into sink, tub, shower, and floor drain traps, and into toilet bowls and tanks. A dry trap also lets sewer gas into the building.
Arrange for someone to check the property
Even a fully winterized building benefits from periodic checks, and many insurance policies require them for vacant properties in winter.
Frequently asked questions
What temperature should I leave the heat at if I'm away?
55°F is the usual recommendation for an occupied-but-empty house over a short absence. For a longer absence in a genuinely cold climate, heat alone is a bet on uninterrupted power. Full winterization removes the risk entirely, and it is what insurers generally expect for a property vacant through a freezing season.
Is pipe insulation enough on its own?
Insulation slows heat loss; it does not add heat. It buys time in a moderate freeze and it will not save a pipe in a sustained one with no heat source. For a run that has frozen before, heat trace cable, or rerouting the pipe out of the cold space, is what actually solves it.
Do I really need to blow out irrigation lines?
In any climate with a hard freeze, yes. Buried irrigation lines and backflow preventers hold water that gravity draining does not remove, and the backflow assembly in particular is expensive to replace. In Utah and Idaho, where pressurized secondary irrigation is common, a missed blowout is a routine first-freeze service call.
Will homeowners insurance cover freeze damage?
Usually, if the home was heated and reasonably maintained. Most policies specifically exclude freeze damage in a home left vacant without heat or without the system being drained. That exclusion is the reason full winterization matters for seasonal properties: without it, a claim can be denied on the terms of the policy you already have.
Related guides
- Frozen Pipes: What to Do Before They BurstA frozen pipe has not necessarily failed yet. Thawing it correctly, and being ready at the shutoff, is what keeps it from becoming a burst pipe.
- What to Do When a Pipe BurstsThe first ten minutes after a pipe bursts determine most of the damage. Here is the order of operations that limits it.
- How to Shut Off Your Water in an EmergencyFind and operate your main water shutoff before you need it. The single most valuable thing a homeowner can know during a plumbing emergency.
- Clogged Drains: When It's an Emergency and When It Isn'tHow to tell a routine blockage from a main line failure, what to try yourself, and why chemical drain cleaner is a bad idea.
Related services
- Frozen Pipe Thawing and RepairProfessional thawing of frozen supply lines, plus inspection and repair of any sections that split while frozen.
- Emergency Burst Pipe RepairA burst pipe releases water continuously until the supply is shut off. Emergency repair covers isolation, pipe section replacement, and pressure testing.
- Emergency Water Heater Repair and ReplacementDiagnosis and repair of water heater failures, including leaking tanks, no hot water, pressure relief discharge, and emergency replacement.
Cost guides
- After-Hours Plumbing Rates ExplainedWhat the overnight, weekend, and holiday premiums actually are, and how to decide whether tonight's problem justifies paying them.
- Burst Pipe Repair CostWhat burst pipe repair costs by location and pipe type, plus the water damage costs that usually exceed the plumbing.
- Water Heater Replacement CostWhat tank and tankless water heater replacement costs, including the code upgrades that appear on the invoice unexpectedly.
Common questions
Related articles
- What Emergency Plumbing Actually Costs, and WhyA plain breakdown of after-hours rates, call-out fees, and the four questions that change your invoice.
- Your Water Heater Is Telling You It Is About to FailTank heaters give several months of warning before they flood a floor. The signs, in the order they usually appear.
- If Your Basement Backs Up When It Rains, Your Pipes Are FineRain-correlated sewer backups are a municipal capacity problem, not a blockage. Clearing your line will not stop it.