Emergencies
How to prevent frozen pipes
Published by Prime Plumbing · Updated · How we write our guides
Short answer
Keep vulnerable pipes above freezing and keep water moving. Insulate pipes in crawl spaces, attics, garages and exterior walls, seal gaps that let cold air reach them, disconnect garden hoses, and during a hard freeze open cabinet doors and let faucets on exposed lines drip. Leave the heat on at 55°F or higher when you are away.
Which pipes freeze first?
- Outdoor faucets and the pipe just behind them
- Lines in unheated crawl spaces, attics and garages
- Pipes in exterior walls, especially under kitchen and bathroom sinks
- Supply lines in mobile homes and under raised houses
What should I do before winter?
- Disconnect and drain garden hoses
- Shut off and drain outdoor faucets that have an indoor valve
- Wrap exposed pipe with foam insulation; add heat cable on the most exposed runs
- Seal holes where pipes, cables and vents pass through outside walls
- Winterize sprinkler systems
What should I do during a hard freeze?
- Let cold and hot taps on vulnerable lines run at a slow drip
- Open cabinet doors under sinks on outside walls
- Keep the garage door closed if water lines run through the garage
- Hold the thermostat steady day and night
Do pipes freeze in warm climates?
Pipes in the South are more exposed, not less. Houses there are built with plumbing in attics, exterior walls and open crawl spaces because long freezes are rare. When one arrives, as in Texas in 2021, damage is widespread. The same steps apply, and knowing where the main shutoff is matters most.
When should I call a plumber?
Call if a faucet stops flowing in freezing weather, or if the same line freezes every winter. A plumber can thaw the pipe safely, check it for splits, and reroute or insulate the run and install frost-free outdoor faucets so it does not happen again.
Common questions
Does letting a faucet drip really prevent freezing?
It helps in two ways. Moving water freezes less readily, and an open tap relieves the pressure that builds between an ice plug and the faucet, which is what actually splits the pipe.
What temperature should I leave the heat on when away?
At least 55°F. For a long absence in winter, also shut off the main water valve and open the faucets to drain the lines.
Further reading from official sources
- Frozen Pipes (American Red Cross)
- Winter Weather (Ready.gov)
This guide is general information for homeowners, not a substitute for an on-site assessment. Plumbing codes and permit rules vary by city and state.