How to Prevent Pipes from Freezing in Cold Weather

Frozen pipes are one of the more damaging things that can happen to a home in winter. When water freezes inside a pipe, it expands - and that expansion can crack or burst the pipe, sometimes causing significant water damage when the ice thaws. For California homeowners, this risk is easy to underestimate. Much of the state rarely sees hard freezes, but homes in inland areas, foothills, and northern regions like Sacramento can absolutely experience overnight temperatures cold enough to freeze exposed pipes.

Which Pipes Are at Risk

Not all pipes in your home are equally vulnerable. The highest-risk locations are:

• Exterior walls: Pipes that run through walls facing the outside of the home have less insulation between them and freezing temperatures.
• Crawl spaces and under-floor areas: Pipes exposed to outside air beneath raised foundations are particularly vulnerable.
• Garages: Unheated garages often drop well below freezing overnight. Any water supply line running through the garage is at risk.
• Outdoor faucets and hose bibbs: These are the most exposed pipes on most homes.
• Attics: Less common for water lines, but some homes route pipes through unconditioned attic space.

In California, many older homes were built with minimal pipe insulation because severe freezes were considered rare. That assumption can cause problems during an unusual cold snap.

Prevention Steps Before a Freeze

Insulate exposed pipes: Foam pipe insulation sleeves are inexpensive - typically around $1 to $3 per linear foot - and easy to install. They slip over the pipe and close with a self-adhesive seam or tape. Focus on pipes in crawl spaces, exterior walls, garages, and anywhere else that gets cold.

Disconnect and drain garden hoses: A hose left connected to an outdoor faucet can hold water that freezes and pushes back into the supply line. Disconnect hoses before the first hard freeze of the season.

Shut off and drain outdoor faucets: Many outdoor faucets have a separate indoor shutoff valve. Close it, then open the outdoor faucet to let any remaining water drain out before temperatures drop.

Insulate or seal crawl space vents: Some homeowners close crawl space vents during cold weather to keep warmer air around the pipes below the floor. This is a reasonable precaution during extreme cold, though it has trade-offs for moisture management.

Know where your main shutoff is: If a pipe does freeze and burst, being able to shut off the water immediately limits the damage. (If you are not sure where it is, see our guide on emergency water shutoffs.)

During a Cold Snap

When temperatures are forecast to drop below freezing - roughly 32 degrees Fahrenheit - overnight or for multiple days:

Let faucets drip: Allowing a slow trickle from faucets fed by vulnerable pipes keeps water moving. Moving water is significantly less likely to freeze than standing water. Even a small drip can prevent a freeze. Focus on faucets on exterior walls or at the end of long pipe runs.

Keep cabinet doors open: Under-sink cabinets on exterior walls trap cold air. Opening the cabinet doors allows warm room air to circulate around the pipes.

Maintain heat indoors: If you are leaving home for an extended period in winter, do not turn the thermostat all the way down. Keeping the home at around 55 degrees Fahrenheit or above is generally enough to protect interior pipes.

Use heating tape on high-risk pipes: Electrical pipe heating tape wraps around vulnerable pipes and keeps them above freezing. It draws a small amount of electricity and is most practical for short runs in attics, crawl spaces, or garages. Follow manufacturer instructions carefully - incorrect installation is a fire risk.

If a Pipe Freezes

If you turn on a faucet and get little or no water during a freeze, a pipe is likely frozen.

1. Leave the faucet open so water can flow once thawing begins.
2. Apply gentle heat to the frozen section - a hair dryer, heating pad, or warm towels work. Start from the faucet end and work back toward the coldest section.
3. Never use an open flame, propane torch, or kerosene heater to thaw pipes. This is a serious fire risk and can also cause pipes to burst from sudden thermal shock.
4. Do not assume the pipe is intact just because it thawed without obvious leaking. Inspect carefully once water flows, and monitor for the next several hours.

If you cannot locate the frozen section or the pipe is in an inaccessible area, call a plumber.

If a Pipe Bursts

Shut off the main water immediately. Then assess the damage - a burst pipe can release a large amount of water quickly. After shutoff, call a plumber. Most burst pipe repairs require cutting out the damaged section and replacing it. Do not try to patch a burst section with tape or epoxy as a permanent fix.

Bottom Line

Sources and editorial notes

Prices and permit requirements vary by location, property, equipment, and scope. Treat price ranges as planning estimates and confirm current requirements with the relevant authority and contractor.

• California Contractors State License Board - when a contractor license is required
• US Department of Energy - Energy Saver
• US Consumer Product Safety Commission - home safety

Related guides

• How Long Do Home Pipes Last? Signs It's Time to Repipe
• How to Winterize Your Home (Checklist for Homeowners)
• What to Do When a Pipe Bursts

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