Frozen Pipes in Winter Weather

Temperatures below freezing can cause pipes in your home to leak due to expanded, frozen water within. Use the tips below to avoid indoor flooding and other dangers.

When it drops below freezing, you should protect indoor sink pipes that are against exterior walls by opening under-sink cabinet doors to allow indoor heat to circulate. During severe cold temperatures allow one indoor faucet to slowly drip cold water. Select the faucet that is the farthest from your front door. Do not leave water running in unoccupied buildings. Set your thermostat no lower than 55 degrees day or night, even if you are away.

 

Prepare Your Pipes

  • Know where your shutoffs are. If an emergency occurs, you’ll need to know how to shut off electricity, gas and water at main switches and valves.
  • Protect water pipes from freezing in exposed or unheated areas (attics, basements and garages) by wrapping them with tape and insulating materials from hardware stores. Follow manufacturers' installation instructions.
  • Drain and remove all outdoor hoses.
  • Caulk around pipes where they enter the house and close all foundation vents to minimize cold wind from blowing into your house. Pipes exposed to drafts from open foundation vents are most at risk of freezing or splitting during cold weather. Close off these vents by sliding cut pieces of wood or Styrofoam into the vent openings (open the vents again in the spring to prevent dry rot).
  • If you have a separate shut-off valve for outside faucets, now is the time to shut it off. Then go outside and turn on all faucets to drain the water out of the pipes.
  • If you don't have a separate shut-off valve, wrap outside faucets or hose bibs (if you choose, foam insulated covers are available for about $3 at hardware stores).
  • Shut off and drain in-ground sprinkler systems. Follow manufacturer' instructions.

 

If Pipes Break or Freeze

If a water pipe breaks, immediately close the main shut-off valve to stop flooding. The shut-off valve can be indoors or outdoors, usually in a basement, crawlspace or garage. If you cannot turn off the main shut-off valve, SPU customers can call (206) 386-1800 and a crew will turn off the water at the meter for a service charge. This phone number is staffed 24/7. Call a plumber to repair or replace the damaged section of pipe as soon as possible.

Thawing frozen pipes

  • If you turn on a faucet and only a trickle comes out, suspect a frozen pipe. Locate the suspected frozen area of the water pipe. Likely places include pipes running against exterior walls or where your water service enters your home through the foundation.
  • Keep the faucet open. As you treat the frozen pipe and the frozen area begins to melt, water will begin to flow through the frozen area. Running water through the pipe will help melt more ice in the pipe.
  • Apply heat to the section of pipe using towels soaked in hot water wrapped around the pipe, an electric heating pad wrapped around the pipe, or an electric hair dryer. Do not use electrical devices if there is standing water. Do not use a blowtorch, kerosene or propane heater, charcoal stove, or other open flame device. A blowtorch can make water in a frozen pipe boil and cause the pipe to explode. All open flames in homes present a serious fire danger, as well as a severe risk of exposure to lethal carbon monoxide.
  • Apply heat until full water pressure is restored. If you are unable to locate the frozen area, if the frozen area is not accessible, or if you cannot thaw the pipe, call a licensed plumber.
  • Check all other faucets in your home to find out if you have additional frozen pipes. If one pipe freezes, others may freeze, too.