Frozen Pipes: How To Tell, How To Thaw and How To Prevent Them

How To Tell If Your Pipes Are Frozen

The first sign is almost always a fixture that produces nothing, or a thin trickle, while the rest of the building runs normally. That points to a specific line rather than the water service as a whole.

• No water or barely a trickle from one faucet while others work fine
• Visible frost, condensation or a bulge on an exposed section of pipe
• A pipe that feels noticeably colder than the ones beside it
• Gurgling, banging or whistling when a tap is opened
• A sewage smell from a drain, which can mean the drain line itself is blocked with ice
• A toilet that will not refill after flushing

At What Temperature Do Pipes Freeze

Water freezes at thirty-two degrees, but pipes inside a building are protected by the surrounding structure, so they usually need outside temperatures around twenty degrees Fahrenheit or lower before they are at real risk. What matters more than the number is how long the cold lasts and how much of the pipe run sits outside the heated envelope.

A sustained cold snap over several days is far more dangerous than a single freezing night, because the cold works its way into wall cavities and crawl spaces that would otherwise stay above freezing. Wind makes it worse, since it drives cold air through gaps in the foundation, around rim joists and through vents.

Why Older Jersey City Buildings Are Vulnerable

Row houses and brownstones built long before modern insulation standards frequently carry supply lines through exterior walls, unheated rear additions and crawl spaces under kitchen extensions. Those runs are the ones that freeze, and they are also the hardest to reach once the pipe splits.

Vacant units and rarely used bathrooms add another layer of risk. When heat is turned down in an unoccupied apartment or a top floor nobody uses, the pipes serving it sit in air that is much colder than the rest of the building. Every winter we open walls on burst lines in exactly those spaces.

How To Prevent Frozen Pipes

Prevention is cheap compared to a burst pipe and a ceiling repair. Most of it comes down to keeping heat near the pipe and keeping cold air away from it.

• Insulate pipe runs in crawl spaces, unheated basements, garages and exterior walls
• Let a cold tap drip on the coldest nights, since moving water is much harder to freeze
• Open vanity and kitchen cabinet doors so heated room air reaches the pipes behind them
• Keep the thermostat no lower than fifty-five degrees even when the building is empty
• Shut off and drain outdoor spigots and hose bibs before the first hard freeze
• Seal drafts around the rim joist, foundation vents and where pipes pass through exterior walls

When To Stop and Call

Call rather than keep working if you cannot find the frozen section, if the pipe runs inside a finished wall or ceiling, or if the frozen line serves the heating system. Those situations either need the wall opened properly or risk turning into a much larger repair.

Call immediately if a pipe has already burst, if water is running anywhere you cannot see, or if the building has lost heat during freezing weather. A building without heat in a cold snap will freeze pipe after pipe, and restoring the heat is the urgent job.

Frequently Asked Questions