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Frozen water lines

Every winter, a few Calgarians will experience freezing water pipes, service lines, meters and water outages. Often, frozen water lines and pipes can be avoided with some simple proactive steps in your home. Learn more about how to prevent freezing, as well as, what to do when you have received a notice from the City or if your pipes are already frozen.

For homes recently affected by flooding, there are some important steps that should be taken to avoid further flood-related damages. Visit our winterization page for more details.

I have received a notice from the City - what should I do?

If your water services is at risk of freezing this winter, you will receive a written notification from the City. Follow the instructions on the notice, which includes:

  • Instructions on how to prevent frozen service lines
  • Notice to run your water when the risk of freezing is increased
  • Specific instructions on running the right volume of water
  • Notice of your water-bill being adjusted for this larger-volume use
  • Notice to turn off your running water when risk of freezing is over

If you have any further questions or concerns, please call 311.

What should I do if my water service freezes?

If your house or basement is flooding, turn off the main water valve and call 311. If you believe your pipes have frozen, turn off water at the main valve and call a plumber.

Check all other faucets in your home to find out if you have additional frozen pipes. If one pipe freezes, others may also freeze. When in doubt, always call a plumber.

How to prevent frozen pipes

Look for cold draughts
Check around your home for areas where water supply lines are in unheated areas and take measures to prevent the flow of cold air in these areas. Common locations include: basement, crawl space, attic, garage, and under kitchen and bathroom cabinets.

Don't forget both hot and cold water pipes in these areas should be insulated. A hot water supply line can freeze just like a cold water supply line if water is not running through the pipe and the water temperatures becomes cold.

Insulate pipes
Consider installing specific products made to insulate water pipes like a pipe sleeve or installing UL-listed heat tape, heat cable or similar materials on exposed pipes.

Find your water shut-off valve
Determine where your water shut-off valve is in your house and learn how to use it. For most homes the shut-off valve is located near the water meter at the point where the water line comes into your home, which usually in your basement.

Protect garage pipes
If you have plumbing in your garage, keep your garage door closed when it's very cold. Pipes in unheated garages or basements should be insulated.

Seal your home from winter
Repair broken windows, check doors and insulate areas that allow cold exterior air to enter.

Be prepared when travelling
Leaving during winter? Keep your thermostat set at 15 degrees or higher, and have someone check your house every second day.

Winterize outside faucets
Make sure the water line to outside faucets (such as your garden hose) is turned off, the hoses disconnected, and the line is drained.

Why do service lines freeze?

Water temperature
During winter, the temperature of Calgary's rivers decreases to around 00 C. At this temperature, if the water stops flowing it can turn to ice. Our water treatment process takes place inside and warms the water slightly to anywhere from 1-3 degrees.

With the water already being this cold as it enters our water distribution system, it takes very little exposure to colder temperatures for it to freeze. That is why it is important to make sure your water service lines are not exposed to colder air during winter months.

Frost depth
This is the depth to which the ground is frozen. In Calgary, frost depth usually reaches an average of seven feet every year. It takes several months to reach this depth and usually occurs in late February or early March.

In early spring, it may seem warmer, but frost is still deep in the ground and stays this way long as it drops below freezing at night. Another factor is if we have colder weather in fall months, the frost depth can exceed seven feet and put service lines at risk.

If the ground surrounding the service lines becomes frozen, it will cool the already cold water in the pipes and they can freeze. When the water stops moving, the temperature can lower quite quickly and freeze the water. This is why it is important to keep the water running; it keeps warmer water moving through the frost zone.