How to Prevent Frozen Pipes in Calgary Winters

Calgary winters are genuinely cold. We're talking about temperatures that regularly drop to -20°C or below, with wind chills that can make it feel even colder. For most of us, that means heavy coats and warming up the car. For your home's plumbing, it means a real risk of frozen pipes — and potentially, a burst pipe emergency that can cause thousands of dollars in water damage.

The good news is that frozen pipes are largely preventable. With a bit of preparation before the cold season hits, you can significantly reduce your risk. This guide covers everything you need to know, from understanding why pipes freeze to practical steps you can take right now.

Why Do Pipes Freeze in Calgary?

Water expands when it freezes. When water inside a pipe freezes, that expansion creates enormous pressure — enough to crack or burst even copper and steel pipes. The pipe itself doesn't necessarily fail at the point where the ice forms; the pressure can build up anywhere along the pipe, causing a failure at the weakest point.

Pipes are most vulnerable when they run through areas of your home that aren't heated: exterior walls, uninsulated crawl spaces, garages, and attic spaces. Pipes in these locations are exposed to outdoor temperatures and can freeze when temperatures drop significantly.

Older homes in NE Calgary and other established neighbourhoods are particularly vulnerable because they may have pipes running through exterior walls without adequate insulation — a construction practice that was common decades ago but is now understood to be problematic in cold climates.

Which Pipes Are Most at Risk?

• Pipes in exterior walls: Any pipe running through an exterior wall without adequate insulation is at risk during cold snaps.
• Pipes in unheated spaces: Garages, crawl spaces, and attic areas that aren't heated can get cold enough to freeze pipes.
• Pipes near exterior doors and windows: Cold air infiltration around poorly sealed doors and windows can freeze nearby pipes.
• Outdoor hose bibs: The outdoor water connection for garden hoses is particularly vulnerable and should be shut off and drained before winter.
• Pipes in vacation properties or homes left unoccupied: If the heat is turned off or set very low, all pipes in the home are at risk.

Prevention: What To Do Before Winter

Insulate Vulnerable Pipes

Pipe insulation (foam pipe sleeves) is inexpensive and easy to install. Wrap any pipes that run through unheated spaces or along exterior walls. Pay particular attention to pipes in the garage, crawl space, and any areas where you've had freezing issues before.

Seal Gaps and Cracks

Cold air can enter your home through gaps around pipes where they pass through exterior walls. Use caulk or spray foam insulation to seal these gaps. This also helps with your home's overall energy efficiency.

Shut Off and Drain Outdoor Hose Bibs

Before the first hard freeze, shut off the water supply to outdoor hose bibs from inside your home and open the outdoor tap to drain any remaining water. If your hose bib doesn't have an interior shut-off, consider having a frost-free hose bib installed.

Know Where Your Main Shut-Off Valve Is

If a pipe does freeze and burst, you need to be able to shut off the water supply immediately. Make sure everyone in your household knows where the main shut-off valve is and how to operate it. See our guide: What To Do Before Your Emergency Plumber Arrives in Calgary.

During Cold Snaps: Keeping Pipes from Freezing

• Keep your home heated to at least 13°C, even when you're away. This is the minimum temperature to prevent pipes from freezing in most Calgary homes.
• Open cabinet doors under sinks on exterior walls to allow warm air to circulate around the pipes.
• Let a trickle of water run from faucets connected to pipes that run through exterior walls. Moving water is much harder to freeze than standing water.
• Keep garage doors closed if there are water supply lines in the garage.

If You're Leaving for an Extended Period

If you're heading away for the holidays or an extended trip during Calgary's winter, take these additional precautions:

• Set your thermostat to at least 15°C — not lower.
• Have a trusted neighbour or friend check on your home regularly.
• Consider shutting off the main water supply and draining the pipes if you'll be away for more than a few weeks.
• Ask a plumber to inspect your home's vulnerable pipes before you leave.

What To Do If Your Pipes Freeze

If you turn on a faucet and get little or no water, or if you notice frost on a visible pipe, you may have a frozen pipe. Here's what to do:

1. Don't panic. A frozen pipe hasn't necessarily burst yet. If you act quickly, you may be able to thaw it before it fails.
2. Open the faucet connected to the frozen pipe. As the ice melts, water will flow through, and having the faucet open relieves pressure.
3. Apply gentle heat to the frozen section if you can locate it. Use a hair dryer on low heat, warm towels, or a heating pad. Never use an open flame.
4. Work from the faucet end toward the frozen section — not from the middle, which can trap steam and increase pressure.
5. Call us if you can't locate the frozen section, if you can't thaw it yourself, or if you suspect a pipe has already burst. Our 24 hour plumber Calgary team can respond quickly.

When a Frozen Pipe Becomes a Burst Pipe

If a frozen pipe has already burst, shut off your main water supply immediately and call us at (403) 771-5925. See our burst pipe repair service page for more information on what to expect. The faster you act, the less water damage you'll face.

For information on how the City of Calgary handles water main breaks and related municipal issues, visit the City of Calgary water services page.