Written & reviewed by Marcus ReedIICRC WRT
Reviewed July 16, 2026· Next review Jan 2027
Quick answer
To prevent burst pipes in winter: insulate pipes in unheated crawl spaces, attics and exterior walls; keep the thermostat at or above 55°F even when away; open cabinet doors under sinks on exterior walls; and let a pencil-thin trickle run from the furthest faucet during hard freezes. Disconnect and drain garden hoses before the first freeze — hose bibs are the most common failure point. Call (888) 840-6512 to reach a certified water damage restoration company in your area; the line is answered 24/7.
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A $10 Problem That Becomes a $15,000 One
A frozen pipe does not burst where the ice forms. Ice expands and blocks the pipe, pressure builds between the blockage and the closed faucet downstream, and the pipe splits at its weakest point — often somewhere else entirely, often inside a wall.
Worse, most bursts are not discovered while frozen. They are discovered when the ice thaws and the split line runs freely into a house where nobody is home. This is why winter pipe losses are consistently among the most expensive residential claims — water damage and freezing claims average close to $14,000 across the industry.
The Pipes That Actually Freeze
Not all of them. The risk sits with pipes in unheated or poorly insulated space:
- Exterior walls, especially on the north side
- Unheated basements, crawl spaces, attics and garages
- Under kitchen and bathroom sinks on outside walls
- Outdoor spigots and any line feeding them
- Sprinkler and irrigation lines
- Anything in a vacation home, or a room you keep closed off
Pipes generally begin freezing when surrounding air drops to about 20°F, though poorly insulated runs exposed to wind can freeze higher.
Before Winter — The One-Afternoon Checklist
| Task | Cost | Payoff |
|---|---|---|
| Disconnect garden hoses, drain and shut off exterior spigots | Free | Eliminates the most common freeze point |
| Insulate exposed pipes with foam sleeves | $1–$3 per foot | The highest return per dollar in the house |
| Seal air leaks near pipes — rim joists, sill plates, cable penetrations | $10–$40 in caulk and foam | A single cold draft freezes an otherwise safe pipe |
| Install insulated covers on outdoor faucets | $5–$10 each | Trivial |
| Blow out irrigation lines | $75–$150 | Prevents an expensive system failure |
| Locate and test your main shut-off | Free | The one that limits the damage when everything else fails |
A seized main valve discovered mid-emergency is its own disaster. Turn it fully off and back on now, while it does not matter. Our emergency shut-off guide covers where to find it.
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During a Cold Snap
Keep the thermostat at 55°F or above, day and night, occupied or not. Setting back at night to save on heating is exactly how the overnight freeze happens.
Open cabinet doors under sinks on exterior walls so heated room air reaches the plumbing. Move household chemicals out of reach of children first.
Let vulnerable faucets drip. A slow trickle from the fixture furthest along the run relieves pressure and keeps water moving. It is not the movement that saves you so much as the open path — an open faucet means pressure has somewhere to go if ice forms.
Open interior doors so heat circulates, including to rooms you normally keep shut.
Keep the garage door closed if any plumbing runs through it.
If You Are Leaving Town
The house does not need to be comfortable, but it does need to be safe:
- 1Set the thermostat no lower than 55°F — never off
- 2Shut off the main and open faucets to drain the system if you will be gone more than a few days
- 3Shut off the supply to the washing machine and ice maker
- 4Have someone check the house every couple of days
- 5Consider a freeze alarm or smart water sensor ($30–$100) — many alert your phone, and some smart shut-off valves close the main automatically
For a home that sits empty every winter, an automatic shut-off valve is the least expensive insurance in the building.
If a Pipe Is Already Frozen But Not Burst
You have a window. Open the faucet that pipe feeds — this relieves pressure and tells you when flow returns. Warm the pipe from the faucet end backwards with a hair dryer, heat lamp, or towels soaked in hot water. Never use a blowtorch, propane heater or any open flame — it is a leading cause of house fires during cold snaps, and it can flash-boil water inside the pipe.
If you cannot reach the frozen section, or flow does not return, call a plumber before it thaws on its own.
If it has already burst, shut the main immediately and see who to call for a burst pipe.
Bottom Line
Insulate exposed runs, seal the drafts reaching them, keep the house at 55°F or above even when empty, drip the vulnerable faucets in a hard freeze, and know where the main shut-off is before you need it. The full list costs less than one hour of emergency water extraction.
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Frequently Asked Questions
- 1Pipes in exterior wall cavities with no insulation -- kitchen and bathroom walls on exterior-facing walls are the most common failure point
- 2Pipes in unheated garages -- especially supply lines to outdoor faucets or hose bibbs that weren't properly winterized
- 3Crawl space pipes -- plastic (PEX, CPVC) pipes exposed to outside air through crawl space vents
- 4Pipes in attic spaces not separated from unconditioned attic air
- 5Outdoor hose bibbs not winterized before first freeze. In regions where hard freezes are rare (Texas, Georgia, Arizona), pipes are often not insulated at all -- making them extremely vulnerable during unusual cold snaps.
- 1Disconnect all garden hoses -- a connected hose prevents proper drainage and traps water in the bibb.
- 2Locate the indoor shutoff valve for each exterior hose bibb -- most homes built after 1980 have a separate shutoff behind each bibb inside the home. Turn it clockwise to close.
- 3Open the exterior bibb fully and leave it open to drain any residual water and equalize pressure. For older homes without interior shutoffs, install frost-free sillcocks ($25-50 at hardware stores) -- they drain automatically when the handle is closed. This is a non-negotiable upgrade in USDA Hardiness Zones 5 and colder.
At what temperature do pipes burst?
Water pipes begin to freeze when the air surrounding them reaches 20 degrees Fahrenheit (-6.7 Celsius) -- typically in uninsulated exterior wall cavities, garage walls, crawl spaces, and attic pipe runs.
However, pipes rarely burst during freezing -- they burst when they THAW and the ice blockage melts, releasing pressure through the section that cracked under expansion. This is why burst pipe flooding often starts hours after temperatures rise above freezing. The American Red Cross threshold for protective action is when outdoor temps drop below 20 degrees Fahrenheit.
Which pipes are most likely to freeze and burst?
The highest-risk pipe locations in order of vulnerability:
Should I let faucets drip to prevent pipes from freezing?
YesAllowing cold-side faucets on exterior walls to drip at a slow but steady rate (a small trickle, not a full drip) relieves pressure in the pipe and keeps water moving, both of which reduce freeze risk.
This is most effective for overnight freeze events or during a 24-48 hour cold snap. Open both the hot and cold sides of any faucet on an exterior wall. The cost of water used (typically $2-5 for a 24-hour drip event) is insignificant compared to even a small burst pipe claim. Do NOT run the dishwasher or washing machine during a freeze event -- concentrate on dripping bathroom and kitchen faucets on exterior walls.
How do I winterize outdoor faucets?
Proper outdoor hose bibb winterization has three steps:
What temperature should I keep my thermostat to prevent pipes from freezing?
Keep your thermostat set to at least 55 degrees Fahrenheit at all times -- even when away on vacation. The 55-degree floor makes sure interior wall cavities stay above the 20-degree freeze threshold even when outdoor temps drop below zero. Do not drop below 55 to save energy during a cold snap -- one burst pipe claim (average $5,000-8,000) costs more than years of incremental heating bills.
If you are leaving for an extended vacation, tell a trusted neighbor or property manager how to access your home and where your water shutoff is. If your home will be vacant for more than 2 weeks during winter, consider a smart thermostat with remote monitoring and a leak detector with a mobile alert.
How much does it cost to fix frozen pipes?
Thawing a frozen pipe before it bursts: often $100–$300 for a plumber visit — the least expensive outcome by far.
If the pipe has already split, add the repair ($150–$850) plus whatever the released water damaged; frozen-pipe bursts frequently flood wall cavities and ceilings, which is why the same event ranges from a service call to a five-figure restoration project.
Who do I call right now for water damage?
Call (888) 840-6512. The line is answered 24 hours a day, seven days a week, and connects you with an IICRC-certified water damage restoration company that serves your area.
Describe what you can see — where the water is coming from, how long it has been there, and whether it smells — and the dispatcher routes you to a crew that handles that kind of loss. If the source is a pipe or an appliance, shut the main water valve first; the call itself takes under two minutes.
Local Expert Help
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Sources
- American Red Cross -- How to Prevent Frozen Pipes(retrieved 2026-07-16)
- Insurance Information Institute -- Water Damage and Freezing Claims Statistics(retrieved 2026-07-16)
- University of Illinois -- When Do Water Pipes Freeze? Threshold Temperature Research(retrieved 2026-07-16)
Methodology: How we source and verify data · Report an error
Disclaimer: HearthDry is an independent educational resource. This article is for informational purposes only and does not constitute professional, legal, or insurance advice. Consult licensed professionals before making decisions about your property or insurance claims.
Professional Equipment
Two Products That Prevent the Most Common Winter Water Damage
Foam pipe insulation protects exposed pipes in crawl spaces and attics. A smart water main shutoff valve automatically cuts water flow when a sensor detects a burst — limiting damage to minutes instead of hours.
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Watch
Source: Top Homeowner — YouTube
Equipment
What each machine actually does
Removes the moisture the structure is still giving off — the machine that decides how long drying takes
See the picks →Moves air across wet surfaces so the dehumidifier has something to take out of the air
See the picks →Finds water behind walls and under floors, and tells you when a material is actually dry
See the picks →Alerts you the moment a leak starts — the cheapest thing on this list and the only preventive one
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