How to Keep Pipes From Freezing: An Adjuster’s Winter Guide

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The Short Answer

Pipes don’t burst because water expands when it freezes — they burst because an ice blockage traps water between the ice and a closed faucet, and pressure spikes until the pipe lets go. Keep your house at 55°F or warmer, insulate pipes in unheated spaces, seal the air leaks that let cold air hit them, and know which faucet to drip during a deep freeze. Do that, and you’ll avoid one of the most expensive — and most commonly denied — winter claims I see.

I’m a licensed property claims adjuster. Every winter I walk into homes with ceilings on the floor and floors buckled like potato chips, all from a pipe that froze, thawed, and split while nobody was watching. Almost all of it was preventable with about an hour of work in the fall. Here’s what actually works.

Why Pipes Burst: It’s the Thaw, Not the Freeze

Here’s the part most people get wrong. Yes, water expands when it freezes. But the pipe rarely splits at the ice blockage itself. What actually happens:

Water freezes in a section of pipe, forming an ice plug.
That plug seals the pipe, trapping liquid water between the ice and a closed faucet.
As more ice forms, pressure builds in that trapped section — we’re talking thousands of pounds per square inch.
The pipe bursts at a weak point, often downstream of the freeze, sometimes feet away from the ice itself.
Nothing leaks yet — because the ice is still blocking the flow.
The temperature rises. The ice melts. And suddenly you have a fully pressurized pipe spraying water through a split — into a wall cavity, an attic, or a crawlspace where nobody sees it for hours or days.

This is why frozen-pipe claims are so destructive. It’s not a drip. It’s a pressurized supply line discharging at full flow, often overnight, often while the house is empty. A single burst supply line can dump hundreds of gallons before anyone notices. That’s why the ceiling is on the floor.

If a pipe does burst on you right now, stop here and go read 5 Things To Do in the First 10 Minutes After You Find Water Damage first — the actions you take in the first hour directly affect both the damage and your claim.

The Highest-Risk Spots in Your House

Frozen pipes aren’t random. They happen where cold air meets water supply lines. Walk through your house with this list:

Exterior walls. Any supply line running through an outside wall — kitchen sinks on exterior walls are the classic — is one cold snap away from trouble. The pipe sits inches from the outside air with only insulation between them.
Crawlspaces. Unheated, vented, and full of exposed plumbing. This is where I see the most freeze bursts in older homes.
Attics. Supply lines to upstairs bathrooms often run through cold attic space. An attic at 20°F with a pipe in it is a burst waiting to happen.
Garages. Laundry or utility sinks in unheated garages freeze fast, especially overnight when the door goes up and down.
Hose bibs and exterior faucets. The number-one freeze point in the entire house. An unprotected hose bib freezes, the ice travels back into the wall, and the pipe splits inside the wall where you can’t see it.
Vacant rooms and additions. That enclosed porch someone turned into a laundry room with the heat vent closed? That’s a claim file waiting to be opened.

Here’s my rule of thumb: if you wouldn’t sleep comfortably in that space without a blanket, don’t trust an unprotected water line in it.

Prevention: What Actually Works

Roughly in order of impact per dollar spent:

1. Insulate the pipes in unheated spaces

Foam pipe insulation sleeves are cheap, take minutes to install, and are the single best return on investment in freeze prevention. Cut them to length, slip them over exposed supply lines in crawlspaces, attics, basements, and garages. Any pipe you can see in an unheated space should be wearing insulation.

Important honesty: insulation slows heat loss — it doesn’t create heat. On a long enough deep freeze, an insulated pipe in a 10°F crawlspace will still freeze. Insulation buys you time and margin. For real protection in the coldest spots, pair it with the next item.

2. Heat tape on the worst offenders

For pipes in the coldest, most exposed locations — the crawlspace run, the attic line to the upstairs bath, the garage sink — electric heat tape (also sold as pipe heating cable) is the real fix. It wraps around the pipe and keeps it just warm enough to prevent freezing, usually with a built-in thermostat that only runs when temperatures drop near freezing.

Two rules: follow the manufacturer’s instructions exactly (overlapping heat tape can overheat), and never use it on a pipe you can’t inspect periodically. It’s a great tool used correctly and a fire hazard used sloppily.

3. Seal the air leaks

Cold air hitting a pipe is what freezes it, and cold air gets in through gaps you’d never notice — around the sill plate, where plumbing penetrates the foundation, dryer vents, the hole where the hose bib passes through the siding. Walk the perimeter of your basement and crawlspace on a cold day and feel for drafts. Caulk and spray foam are cheap. A pipe in a draft-free 40°F crawlspace is fine; the same pipe in a 15°F wind tunnel is not.

4. Keep the heat at 55°F or above — always

This is the one people argue with, and it’s non-negotiable. If you leave for a weekend, a week, or the whole winter, the thermostat stays at 55°F minimum. Not 50. Not “I’ll turn it down to save money.” Fifty-five.

The fuel you save dropping from 55 to 45 is nothing compared to a $15,000–$40,000 water loss. And as I’ll explain below, letting the house go cold is exactly what gets claims denied.

5. Open the cabinets

For sinks on exterior walls, open the cabinet doors during cold snaps so warm room air circulates around the pipes. It sounds too simple to matter. It matters — I’ve seen the difference in claim files. Closed cabinet + exterior wall + single-digit night = frozen trap arm.

6. Shut off and drain exterior hose bibs

Before the first hard freeze: shut off the interior valve to each hose bib, open the outside faucet to drain it, and leave it open for winter. Then put an insulated cover over each exterior faucet.

And disconnect the garden hoses. A hose left attached traps water in the bib, and that trapped water freezes back into the wall. I see this exact fact pattern every single winter — it’s practically a seasonal tradition in my claim files. If you only do one thing from this article, disconnect the hoses.

The Truth About Dripping Faucets

“Just let the faucet drip” is the most repeated — and most misunderstood — freeze advice in existence. Here’s what’s actually true:

It works, but not for the reason people think. A dripping faucet doesn’t keep water warm. What it does is give the trapped pressure somewhere to go. Remember how pipes burst: pressure builds between the ice blockage and the closed faucet. An open faucet — even a slow drip — relieves that pressure. No pressure spike, no burst. The ice may still form, but the pipe survives it.

Which faucet matters. Drip the faucet farthest from where the water enters the house. That’s the one at the end of the longest run of vulnerable pipe — keeping water moving through the whole run protects all of it, not just the last fixture.

Hot and cold both. If both lines run through the cold space, drip both — or at least a faucet with a mixer set in the middle. The cold line is the usual suspect, but hot water lines freeze too (and the water heater’s supply side is always full).

When to do it: nights forecast below about 20°F, or anytime temperatures will sit in the teens for more than a few hours. A drip the width of a pencil lead is plenty — you’re relieving pressure, not running a bath.

The downside is real: you’re paying for water. But a night of dripping costs pennies. A burst pipe costs thousands. The math isn’t close.

What To Do If You Lose Heat in Winter

Power outage, furnace failure, fuel delivery missed — it happens, and the clock starts immediately. Your pipes start freezing when the interior temperature drops into the 40s and keeps falling.

Shut off the main water valve if you can’t restore heat within a few hours. No pressure in the lines means a freeze can’t become a burst — the worst case is inconvenience, not a flood.
Open all faucets (hot and cold) to drain the lines after shutting the main. Start upstairs, work down.
Drain the water heater only if you’re comfortable doing it — at minimum, it won’t burst from freezing if the house goes truly cold for days. (If you’re unsure, leave the heater alone and focus on the supply lines.)
Don’t use a torch or open flame to thaw a frozen pipe. I have adjusted fire claims that started as freeze claims. A hair dryer or heat gun on low, worked along the pipe, is the safe way.
When heat returns, thaw slowly and watch. Turn the main back on gradually, check every fixture and every ceiling below a plumbing run, and leave cabinet doors open. Remember: the burst reveals itself at the thaw, not the freeze — inspect like you expect to find something.

If you’re going to be away and the forecast turns brutal, this same shutoff routine is your best insurance. A dry house can’t flood.

What Adjusters See Denied: The Neglect Exclusion

Now the part that costs people the most money. Frozen-pipe bursts are generally a covered peril — sudden and accidental water damage, same as I describe in Does Homeowners Insurance Cover Water Damage?. But there’s an exclusion that kills these claims regularly:

If you leave the home unheated — or vacant without winterizing it — the carrier can deny the loss as neglect.

The fact patterns I see denied:

Snowbird left the heat at 45°F (or off entirely) to save on fuel. Pipe froze in January. Denied — failure to maintain heat.
Vacant property between tenants with the water still on and no winterization. Denied — vacant-home neglect.
Foreclosure or estate property sitting unheated for months. Denied.
Heat shut off for nonpayment and nobody told the carrier. Denied — and the homeowner’s own inaction caused the exposure.

Most policies require you to either maintain heat in the building or shut off the water supply and drain the system if the home will be unoccupied. “Unoccupied” has a specific definition in your policy — usually 30 or 60 days — and vacant homes often need a separate vacancy permit or endorsement. If your house will sit empty this winter, call your agent before it happens, not after the ceiling collapses.

The bottom line on coverage: a burst pipe in a lived-in, heated home is a covered claim. A burst pipe in a home you let go cold is a denial letter. The difference is entirely in your control.

For the full fall prep list that keeps you out of both categories, see my Fall Home Maintenance Checklist.

Bottom Line

Pipes burst from pressure trapped behind ice — not from the ice itself. Insulate the exposed runs, put heat tape on the worst of them, seal the air leaks, keep the thermostat at 55°F or above no matter what, disconnect the hoses, and drip the farthest faucet on the coldest nights. If you lose heat, shut the water off before the freeze becomes a flood. And if the house will sit empty this winter, either keep it heated or winterize it properly — because an unheated vacant home with the water on is the fastest route to a denied claim I know.

An hour of prevention in October beats a month of repairs in February. Every time.