Seasonal guides · 4 min read
A frozen pipe is a warning; a burst one is a flood. Where pipes freeze in Calgary homes, how to thaw one safely, and the one valve everyone in the house should be able to find.
Published
Pipes rarely freeze in the middle of a heated house. They freeze where cold air reaches them: outside walls, cantilevered floors, garages, crawl spaces and the cabinet under the kitchen sink.
The damage usually is not done while the pipe is frozen. Ice expands, splits the pipe, and the water arrives when it thaws — often in the middle of a chinook, when nobody is watching for it.
The cheap part. Most of it costs nothing.
Know where the main shut-off is
Usually beside the water meter where the line enters the house, often in the basement. Make sure it turns, and make sure everyone at home can find it in the dark. It is the difference between a wet floor and a flooded basement.
Find your cold spots
If a pipe froze last winter, it will try again. Kitchen sinks on outside walls, bathrooms over garages and lines in bump-outs are the usual places. Foam pipe sleeves are inexpensive and take minutes to fit.
Deal with the outside taps
Disconnect hoses, close the indoor isolation valve for each outside tap and drain the line. Our winter prep guide walks through it step by step.
Keep the heat steady
Do not drop the thermostat much below 16°C, even overnight or while you are away. The saving is small next to one burst pipe.
When Environment Canada issues a warning for Calgary, two more things help.
Open the cabinets
Open the doors under sinks on outside walls so warm room air reaches the pipes behind them.
Let a tap drip
A thin, steady drip from the tap farthest from where water enters the house keeps water moving and relieves pressure if ice does form.
You will know: you turn a tap on and get a trickle or nothing, while other taps work.
Leave the tap open
Open the affected tap so melting water has somewhere to go and pressure can escape as the ice clears.
Warm it gently
Work from the tap back toward the frozen section with a hair dryer, a heating pad or warm towels. Raise the room temperature and open the cabinet doors. Be patient — it can take a while.
Look for the split before it thaws
Check the pipe along its length for a bulge or crack. If you find one, shut the main valve before you thaw it, or it will leak the moment the ice melts.
Never use a torch, a propane heater or any open flame to thaw a pipe. It can start a fire inside the wall and can make a pipe burst. If you cannot reach the frozen section, or it is inside a wall or ceiling, call a plumber.
Speed matters more than anything else here.
Shut off the main water valve
Do this first, before anything else. Then open the lowest tap in the house to drain the lines.
Keep away from electrics in standing water
If water is near outlets, the panel or appliances, do not walk through it. Shut off power to that area at the panel only if you can reach the panel safely and dry.
Photograph it, then call
Take photos before you clean up — your insurer will want them. Then call a plumber. Our emergency page lists firms whose hours say someone answers overnight.
An empty house in a cold snap is the most common setting for a burst pipe:
These lists are built from what each firm states on its own website, so they are who says they do the work rather than our recommendation of who does it best.