Frozen pipes are the most predictable plumbing problem in a Portland winter, and one of the most preventable. A pipe that freezes can split, and when the ice melts the leak begins, often inside a wall or ceiling. Here's what puts pipes at risk, what to do before and during a cold snap, and how to thaw a pipe safely if one freezes anyway. For every plumbing service, see our main page on plumbers in Portland, ME.
Why Portland pipes freeze
Portland's average January low is about 15.6°F, and the city sees roughly 10 nights a year at or below 0°F, according to NOAA climate data. Consumer Reports says frozen pipes usually happen below 20°F, though they can freeze above that when uninsulated pipes run through unheated spaces. Add Maine's older housing, with 23.4% of homes built before 1940 compared with 12% nationally, and you get a lot of pipes in places that were never designed to stay warm.
Which pipes are most at risk
The American Red Cross lists these as the most likely to freeze:
- outdoor hose bibs, swimming pool supply lines and sprinkler lines
- pipes in basements, crawl spaces, attics and garages
- pipes in kitchen cabinets
- pipes on exterior walls with little or no insulation
Before winter
- Shut off the supply to outdoor hose bibs, then open the outdoor faucets to drain them.
- Disconnect and drain garden hoses.
- Insulate exposed pipes with pipe sleeves, heat tape or heat cable, as the Red Cross suggests.
- Find your main shut-off valve and make sure it turns. See how to find and use it.
- If your heat is a boiler, have it serviced before the cold arrives. See boiler repair.
During a cold snap
- Keep garage doors closed if water lines run through the garage.
- Open cabinet doors under sinks on exterior walls so warm air reaches the pipes. If you have small children, move cleaning products out of reach first.
- Let faucets fed by exposed pipes drip. Moving water is much less likely to freeze.
- If you're going away, keep the thermostat at 55°F or higher. For longer absences, read how to protect a vacant home.
If a pipe freezes
Open the faucet
Melting ice needs somewhere to go, and running water helps the thaw.
Warm it gently
A hair dryer, heating pad, space heater at a safe distance or towels soaked in hot water.
Keep going until pressure is back
Then check other faucets, since more than one pipe may be frozen.
No open flames
Never use a blowtorch, kerosene or propane heater, charcoal stove or any open flame.
Consumer Reports warns that a frozen pipe may already have burst. Watch it as it thaws, and if water appears, shut off the main valve and see frozen and burst pipe repair.
When to call a plumber
Call if you can't find or reach the frozen section, if it's inside a wall or ceiling, if a pipe has split, or if the same pipe freezes every winter. A plumber can thaw it safely, repair the damage and insulate or reroute the line so it doesn't happen again.