Skip to content
Cold facts on frozen pipes
Fixing a pipe leak isn't difficult if you're home when the pipe bursts, and have solder, flux and a propane torch in the toolbox. That's for copper pipe; it's even easier with plastic. But things can turn ugly at 3 a.m. when you stumble down the basement stairs searching for that gushing sound and step into ankle-deep water.
It will probably be a cold and windy night when a small air leak near a pipe turns standing water into solid ice. That freezing is forceful enough to shatter plastic and split open metal. And even a one-eighth-inch split can gush 250 gallons a day.
If you're not home, the spewing water can flood large areas, short out electrical appliances (including the furnace), and ruin carpets and furniture.
It happens in a quarter of a million homes every winter, according to State Farm Insurance -- and probably many more that don't file claims -- all stemming from freezing pipes, a problem that's easy enough to prevent.
INSULATE, SEAL AIR LEAKS
On new construction and remodeling work, keep water pipes out of exterior walls. Builders and plumbers can usually avoid these troublesome installations, say, by pipes for sinks mounted on exterior walls through the floor of a vanity instead of through the wall. When exterior walls are the only choice, water pipes need extra protection. First, wall insulation should be tucked behind the pipes. Covering them with insulation batts almost guarantees a freeze-up. It also helps to protect pipes with snap-on foam tubes. In existing homes where you don't want to dismantle a cabinet and cut open the drywall behind it, use spray foam in a can.
You can shoot foam into the wall around pipes where the material expands to fill cavities before drying. It insulates and also blocks airflow in the wall. Finally, thoroughly caulk all exterior joints on the outside wall anywhere near the pipes. If there is room -- and there often is around exterior water spigots -- use spray foam from the outside, too.
CLEAR EXTERIOR FAUCETS
Any exterior faucet -- and the garden hose attached to it -- is bound to freeze unless you remove the water. After disconnecting and draining the hose, close the cutoff valve inside the house on the line that feeds the faucet. Then open the outside faucet and drain any remaining water before closing it for the winter. If you don't have an interior cutoff valve just for this fixture, either install one just inside the house, or replace the exterior fitting with an anti-freeze faucet.
INSTALL HEAT TAPES
If there are pipes in cold locations and you can't reroute them or provide enough insulation, heat tapes can prevent freezing.
The tapes look like electrical extension cords, but convert electricity into heat. You plug the tape into a grounded outlet and spiral wrap the length around a water pipe. Most tapes have a built-in thermostat that automatically calls for power as the temperature drops near freezing, and cuts power off as the temperature rises.
It wastes some water, but if you don't get around to any anti-freeze improvements, let water drip from faucets at exterior walls overnight when the house is cold. It also helps to open cabinet doors around fixtures to let warmer indoor air circulate near pipes at exterior walls.
Water pipes will leak if you inadvertently drive a nail into them, and sometimes due to vibration, bad connections, corrosion or just age. But the most likely culprit is freezing water that has enough force to shatter plastic and split open copper. Whatever the source of trouble, it pays to know how to deal with leaks in case the plumbing system starts gushing in the middle of the night.
Limit the damage from a leak by closing the nearest supply valve. There's one installed near every plumbing fixture in the house. Sinks, for instance, have hot and cold cutoffs tucked under a vanity or countertop, while toilets normally have a cold cutoff valve low on the wall nearby. There is also a main cutoff that shuts off water to every supply line. It's normally near the meter where the municipal water line enters the house, or where the line from a private well enters.
Plumbing systems have many branch circuits, so you should be able to isolate the damaged line and keep water flowing elsewhere. This allows you to deal with the leak at your leisure -- or call a plumber the next day.
Once you close the appropriate valve, even a gushing leak will subside.
If you don't have the modest set of tools and supplies to repair a leak properly, wedge toothpicks or some other water-stopping wedge into pinholes or small joint leaks. If you can dry the pipe, spiral-wrapped layers of duct tape may also keep water from seeping through a small leak.
A more reliable temporary fix is a flexible pressure patch. This does not require a propane torch or melted solder and typically stops leaks completely, even if you turn the water back on and don't get around to a permanent repair till the next day. You can use it on copper and plastic pipe. The idea is to cover the puncture with a piece of waterproof material (a sliced open section of garden hose works well), and seal it at each end of the puncture with a band clamp- the kind used on automotive hoses. The only tools you need are a knife or scissors to cut the patch and a screwdriver to tighten the clamps.
With plastic or copper, cut off the supply to the leak on one side and open a faucet on the other. Then cut away the damaged section and allow the pipe to drain and dry. The most reliable procedure is to dry-fit all the new pieces until you get them right, then disassemble them and start the permanent repair.
Cut through plastic pipe with a hacksaw or any sharp saw. For best results, make a square cut and remove any burrs along the edges. For common PVC pipe, apply primer (it preps the surfaces), then add cement to all mating parts according to label directions and rebuild the repair. The cement melts the surfaces of joined pipes, making the new pieces as strong and watertight as unbroken pipe.
Copper is more difficult to repair because connections are sealed with solder. You'll need a propane torch, flux paste, which draws molten solder fully into the joints, and a coil of solder. Draining the line is crucial. A propane torch can make copper hot enough for solder to flow. But if the pipe isn't drained, heat will dissipate boiling water instead of heating metal.
Where new fittings join old pipe, use sandpaper or steel wool to brighten the mating surfaces, removing all corrosion. After you test fit the new sections, disassemble them and coat mating surfaces with flux paste. Build one connection at a time, applying the torch flame to the joint until the solder melts, filling the joint.
You need to protect yourself from dripping solder and be sure that that the propane flame does not ignite nearby combustibles. In tight spots, you can back up the pipe with a piece of drywall wrapped in tin foil to shield nearby framing and plywood.