How to Prevent Frozen Pipes in London, Ontario (and What to Do If One Freezes)

When London gets a run of nights at minus 15 or colder, frozen pipes start showing up. The damage usually isn't the frozen pipe itself. Ice expands, the pipe splits, and you only find out when it thaws and water starts pouring into a wall or the basement. A few small jobs now make that much less likely.

Where pipes freeze

• Pipes along outside walls, especially under kitchen and bathroom sinks
• Outdoor taps and the pipe that feeds them
• Unheated spaces: garages, crawl spaces and cold rooms
• Where the water line comes into the house, often near a basement wall

How to prevent frozen pipes

• Shut off and drain outdoor taps. Close the shut-off valve inside, open the outdoor tap to drain it, and take the hose off. There's a step-by-step video on our Tips & Guides page.
• Insulate exposed pipes with foam pipe sleeves from any hardware store. Focus on pipes in unheated areas and along outside walls.
• Seal drafts where cold air reaches pipes: gaps around the main water line, dryer vents, and holes where cables come in.
• Keep the heat on. Don't let the thermostat drop below about 15 °C, even when you're away.
• Open cabinet doors under sinks on outside walls during cold snaps so warm air can reach the pipes.
• Let a cold tap drip on the coldest nights if a pipe has frozen before. Moving water is much less likely to freeze.
• Know where your main shut-off valve is, and check that it turns.
• Going away? Ask someone to check the house regularly. Many home insurance policies require it during the heating season, so check yours.

What to do if a pipe freezes

1. Find out how far the problem goes. Run several cold taps. If at least one works, the freeze is probably inside your home. If no water comes out anywhere, it may be the service line. Call the City of London's 24-hour water line at 519-661-4739.
2. Open the tap the frozen pipe feeds, so water can flow out as it melts.
3. Warm the pipe gently with a hair dryer, a heating pad or warm towels, starting from the tap end and working back. You can also warm the room with a space heater, keeping it well away from anything flammable.
4. Never use an open flame or a torch. It can start a fire inside the wall and damage plastic pipes.
5. Check for leaks once water is flowing again. If you see water, shut off the main valve straight away.

The City is responsible for the water service up to your property line. The pipes from there into and through the house are the owner's. If you rent, let your landlord know.

Ice dams: the frozen-water problem on your roof

Those big icicles along the eaves are a warning sign. Heat escaping through the attic melts snow on the roof, it refreezes at the colder edge, and the ice backs water up under the shingles. Clean gutters help, but the real fix is usually better attic insulation and ventilation. Our attic insulation guide explains how to check yours.

Get it done before the deep freeze

ApexPlus can insulate exposed pipes, shut down outdoor taps, seal drafts and check your attic in a single visit. See our full late-fall home checklist, or book a winter-prep visit.