Frozen and burst pipes: how to prevent them and what to do when one breaks

Updated November 10, 2026 · KeystoneProGuide editorial team

Why do pipes burst in the cold?

Because water expands when it freezes. The American Red Cross says the expansion puts tremendous pressure on whatever holds the water, metal or plastic, and that no matter the strength of a container, expanding water can break a pipe. The Better Business Bureau adds a second risk: a pipe weakened by freezing can crack when hot water suddenly warms it again.

Southeastern Pennsylvania winters are cold enough for this to be routine. At the National Weather Service's Philadelphia station, the normal low is below freezing in December, January and February, with January lowest at 26 degrees Fahrenheit.

Which pipes freeze first?

The Red Cross names three groups:

• pipes exposed to severe cold, such as outdoor hose bibs, pool supply lines and sprinkler lines
• supply pipes in unheated spaces inside the house: basements, crawl spaces, attics, garages and kitchen cabinets
• pipes on exterior walls with little or no insulation

When a pipe does freeze, it says the likely spots are against exterior walls or where the water service comes through the foundation. The Philadelphia Water Department singles out the water meter area, which it says should be kept above 40 degrees, and drafty windows near meters and pipes, which it says to repair or seal with plastic and caulk.

How do you keep pipes from freezing?

Insulate before the season, then manage the cold nights. Before winter, the Red Cross suggests insulating attics, basements and crawl spaces, insulating both hot and cold pipes in unheated areas, and considering pipe sleeves or UL-listed heat tape or heat cable on exposed pipes. It suggests draining sprinkler and pool lines as their makers direct, without antifreeze unless told to use it. The BBB suggests frost-proof faucets on outdoor spigots.

When a hard freeze is forecast, the Water Department's trigger is temperatures below 32 degrees, especially for two days or more. Then:

• let a faucet drip if those pipes have frozen before or run through a space you cannot keep warm; the Red Cross specifies the cold tap
• open cabinet doors under kitchen and bathroom sinks so warm air reaches the pipes, moving cleaners out of children's reach
• keep the thermostat at the same setting day and night
• keep garage doors closed if supply lines run through the garage
• check the flow at your faucets at bedtime and on waking, since reduced flow is the first sign of freezing

If you will be away, the Red Cross says to leave the heat on at no lower than 55 degrees, and the Water Department says a property left empty in cold weather should have its plumbing drained and winterized.

What should you do if a pipe has frozen but not burst?

Find out whether it is your pipe. The Water Department suggests asking a neighbor: if they have no water either, it may be a main break; if they do, your pipes have likely frozen. Then keep the faucet open so meltwater can run out, and warm the frozen section gently. The Red Cross lists an electric heating pad, a hair dryer, a space heater kept away from flammable materials, or towels soaked in hot water, and rules out blowtorches, kerosene or propane heaters, charcoal stoves and any other open flame. Keep heating until full pressure returns, then check every other faucet, because the Red Cross says that if one pipe freezes, others may too.

Call a licensed plumber if you cannot find the frozen section, cannot reach it, or cannot thaw it.

What should you do when a pipe bursts?

• Shut off the water at the house-side valve near the meter. The Water Department says to find this valve before an emergency.
• Check the meter once things thaw; in Philadelphia, a leaking meter is reported on (215) 685-6300.
• Call a licensed plumber. The Water Department says it will not repair customer pipes, even outside the home, and that calling its hotline about a broken house pipe wastes time you need to find a plumber.
• Call your insurer. The BBB suggests checking what your policy covers for plumbing emergencies and what its filing requirements are. Philadelphia's Department of Revenue cautions that ordinary homeowner's insurance may not cover plumbing defects on the pipes outside the house.

What does a burst pipe cost?

Angi gives $1,000 to $4,000 to repair burst pipes, and notes that damaged drywall may have to come out and go back. HomeAdvisor puts water damage restoration at $1,360 to $6,300, separate from the plumbing repair, and says plumbers typically do not do that cleanup. Emergency rates are higher too: Angi says 1.5 to 3 times the business-hours rate.

How do you hire safely in a hurry?

A freeze is when storm chasers appear. The BBB describes them as contractors who go door to door after severe weather and disappear after taking your money, and warns against "today only" offers and demands for full payment up front. Get a written contract with the pricing and scope, and a receipt for every payment.

The law gives some room for genuine emergencies. Pennsylvania's construction code lets an emergency repair go ahead before the permit, if the application is filed within 3 business days. The Attorney General's office says emergency work can fall outside the home improvement law, but only when the emergency meets the consumer protection law's criteria and the contractor obtains the emergency waiver that law requires. Read what you sign.

What should you check in spring?

Outdoor lines. The EPA says to inspect an in-ground irrigation system each spring for frost damage before turning it on. What you can fix yourself covers small repairs, the maintenance calendar covers the rest of the year, and licensed plumbers are on the plumbers directory page.

Sources

1. Preventing & Thawing Frozen Pipes, American Red Cross
2. All About Frozen Pipes, Philadelphia Water Department
3. Climate Normals for KPHL, National Weather Service
4. BBB Tip: Hiring a plumber during winter storms, Better Business Bureau
5. How Much Does Plumbing Repair Cost? [2026 Data], Angi
6. How Much Does a Plumber Cost in 2026?, HomeAdvisor
7. Frequently Asked Questions: Home Improvement Contractor Registration, Pennsylvania Office of Attorney General
8. 34 Pa. Code § 403.62. Permit requirements and exemptions., Commonwealth of Pennsylvania (Pennsylvania Code)
9. Fix a Leak Week, U.S. Environmental Protection Agency (WaterSense)
10. Follow these tips to get ready for pipe repairs, City of Philadelphia, Department of Revenue