How to tell
On a very cold day, one tap gives nothing or only a trickle while the others work. The pipe feeding it usually runs along an outside wall, through an unheated garage or crawl space, or under a kitchen sink on an exterior wall. If no tap in the house works, the freeze may be where the water service comes in, near the meter.
What to do
- Open the affected tap a little so melting water has somewhere to go.
- Warm the pipe slowly with a hair dryer, a space heater kept well back, or warm towels. Start nearest the tap and work back.
- Open the cabinet doors under sinks on outside walls so house heat reaches the pipes.
- Keep warming until full flow comes back, then check the pipe along its length for drips.
What not to do
- Do not use a torch, propane heater or any open flame. It can start a fire inside the wall and can overheat the pipe.
- Do not bang on the pipe to break up ice.
- Do not leave a space heater running unattended near anything that can burn.
When it has already split
A frozen pipe often cracks without leaking, because the ice plugs the crack. It starts leaking as it thaws. Know where your main shutoff is before you start warming the pipe, and turn the water off as soon as you see water where it should not be.
If it keeps happening
A pipe that freezes every winter is telling you it is in a cold spot. The fix is usually insulating it, sealing the draft near it, or rerouting a short section away from the outside wall. Mention that it is a repeat when you call.