How to Prevent Burst Pipes in Winter: The Complete Homeowner Checklist

Frequently Asked Questions

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: (1) Pipes in exterior wall cavities with no insulation -- kitchen and bathroom walls on exterior-facing walls are the most common failure point; (2) Pipes in unheated garages -- especially supply lines to outdoor faucets or hose bibbs that weren't properly winterized; (3) Crawl space pipes -- plastic (PEX, CPVC) pipes exposed to outside air through crawl space vents; (4) Pipes in attic spaces not separated from unconditioned attic air; (5) Outdoor 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.

Should I let faucets drip to prevent pipes from freezing?

Yes -- allowing 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: (1) Disconnect all garden hoses -- a connected hose prevents proper drainage and traps water in the bibb. (2) Locate 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. (3) Open 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.

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 ensures 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.