Burst and frozen pipes in the Central Valley: prevention and first steps

Frozen pipes are less common in the Central Valley than in snow country, but they do happen. Stockton’s long-running weather station averaged about 22 nights a year at or below 32°F (1948-2005 records), mostly in December and January, and recorded lows of 16-17°F. The pipes that freeze first are outdoors, in attics, garages and crawl spaces, and along poorly insulated exterior walls. Water expands as it freezes, and the crack often shows up only when the ice melts and water flows again. To prevent it, insulate exposed pipes, let a faucet drip on the coldest nights, open sink cabinet doors, and know where your main water shutoff is. Never thaw a pipe with an open flame.

Safety first

• Call 911 for a gas smell, sparking, water spraying onto outlets, lights or the electrical panel, or an injury.
• Sagging ceiling: a pipe that bursts in the attic can soak drywall until it gives way. Keep people out of any room with a bulging or dripping ceiling, and don’t turn on its lights or ceiling fan.
• Electricity: CDC advises turning off power at the main breaker if circuits or equipment are wet or near water. Only do this if you can reach the panel without standing in water.
• No open flames: the Red Cross says never to thaw pipes with a blowtorch, kerosene or propane heater, charcoal stove or any other open-flame device.
• Heating safely: keep space heaters away from anything flammable. Ready.gov says to run generators and grills only outdoors, away from windows, and never to heat your home with a gas stove or oven. Make sure you have working carbon monoxide detectors.

How cold does it get here?

The Western Regional Climate Center’s period-of-record summary for the Stockton weather station (1948-2005) shows:

• About 22 days a year with a low at or below 32°F on average.
• About 7.9 of those days in December and 7.9 in January, 3.2 in February, and about 2 in November. March averages about one.
• Record lows of 16°F (January 11, 1949) and 17°F (December 22, 1990).

A single night that barely reaches freezing is less of a threat than a run of nights in the 20s, especially for pipes outside the insulated part of the house. When the National Weather Service issues a freeze warning for the valley, take that as your cue to protect your pipes.

Which pipes are most at risk

The Red Cross lists the pipes that freeze most often:

• Outdoors: hose bibs, swimming-pool supply lines and sprinkler lines.
• Unheated spaces: supply pipes in crawl spaces, attics, garages and kitchen cabinets.
• Exterior walls: pipes that run along exterior walls with little or no insulation.

Around here, also check exposed irrigation backflow assemblies, pipes to and from a water heater in the garage, and any plumbing added in an attic during a remodel.

Prevention before a cold snap

The Red Cross recommends:

• Drain and store. Drain pool and sprinkler supply lines following the manufacturer’s or installer’s directions (no antifreeze unless directed). Remove, drain and store outdoor hoses.
• Hose bibs: close the inside valves that supply outdoor hose bibs, then open the outside bibs so they can drain. Leave them open.
• Insulate: add insulation to attics, basements and crawl spaces. Insulate both hot and cold pipes in the garage and under cabinets, using pipe sleeves or UL-listed heat tape or heat cable.
• Garage doors: keep them closed if water lines run through the garage.
• Cabinet doors: open kitchen and bathroom cabinets so warm air reaches the pipes. Move cleaners out of children’s reach.
• Drip: on very cold nights, let cold water drip from faucets served by exposed pipes. Even a trickle helps keep a pipe from freezing.
• Thermostat: keep it at the same setting day and night. If you travel, leave the heat on at no lower than 55°F.

Find your main shutoff before you need it

Most homes have a main shutoff where the water line enters the house, often in the garage or near a front hose bib. There is also a valve at the meter box near the street or sidewalk; that one may belong to the water utility and need a meter key. Find yours now:

• Test it. Make sure it turns, clockwise to close.
• Label it. Make sure everyone in the house knows where it is.

Also learn where the fixture valves are under sinks, behind toilets and on the water heater’s cold supply.

If a pipe is frozen

The Red Cross steps:

1. Suspect a freeze if a faucet gives only a trickle. Likely spots are exterior walls and where the water line enters through the foundation.
2. Keep the faucet open. As the ice melts, running water helps melt the rest.
3. Apply gentle heat to that section of pipe. Use an electric heating pad wrapped around it, a hair dryer, a portable space heater kept away from anything flammable, or towels soaked in hot water.
4. Keep heating until full water pressure returns.
5. Call a licensed plumber if you can’t find the frozen section, can’t reach it, or can’t thaw it.
6. Check every other faucet. If one pipe froze, others may have too.

Keep electrical devices away from water. Have someone ready at the shutoff while you thaw, because a pipe that cracked while frozen will start leaking as soon as it thaws.

If a pipe bursts

1. Close the main shutoff.
2. Cut power to wet areas if you can do it from dry ground.
3. Open faucets at the lowest point of the house to drain the lines.
4. Move belongings out of the water, and take photos and video before cleanup for your insurer.
5. Call a licensed plumber to repair the pipe.
6. Call a licensed contractor if water got into walls, ceilings, insulation, cabinets or flooring. CDC’s guidance is to clean up and dry within 24 to 48 hours if possible. Water inside walls and under floors can’t be dried or confirmed dry by looking at the surface.

Not every burst pipe is a frozen pipe. Corroded fittings, failed supply lines and high water pressure cause leaks all year. The same first steps apply.

This guide is general information. For work on your plumbing, rely on a licensed plumber.