How to Prevent Frozen Pipes This Winter in Ontario

Ontario winters are no joke. When temperatures drop below -15°C, unprotected pipes freeze in hours. When they freeze, they burst. And when they burst, you are looking at thousands in water damage before you even know what happened. Here is the complete checklist to protect your home.

Why Ontario Homes Are Especially Vulnerable

Southwestern Ontario sees rapid temperature swings — warm spells followed by sudden deep freezes. This freeze-thaw cycle is brutal on plumbing. Pipes expand and contract, joints loosen, and small cracks become major failures. Older homes in St. Thomas, London, and surrounding communities often have pipes in unheated crawl spaces, exterior walls, or garages — all prime locations for freezing.

The Complete Winter Plumbing Checklist

1. Insulate Exposed Pipes

Any pipe in an unheated area — basement, crawl space, attic, garage, or exterior wall — needs insulation. Foam pipe insulation sleeves are inexpensive and available at any hardware store. For extreme cold zones, consider heat tape, which actively warms the pipe when temperatures drop.

Pro tip: Do not forget the pipe elbows and joints. These are the weakest points and the first to freeze. Use insulation tape to wrap fittings that sleeves cannot cover.

2. Seal Air Leaks

Cold air entering through gaps around windows, doors, and foundation cracks is what freezes pipes fastest. A pipe in a 5°C basement will not freeze. A pipe with a direct draft of -20°C air hitting it will. Use caulk and weatherstripping to seal every gap near plumbing.

3. Keep Cabinet Doors Open

Kitchen and bathroom sinks on exterior walls are high-risk. Opening the cabinet doors allows warm indoor air to circulate around the pipes. It is a 2-second habit that can prevent a costly emergency call.

4. Let Faucets Drip

During extreme cold snaps — below -20°C — let faucets drip slightly. Moving water is much harder to freeze than standing water. Yes, it wastes a small amount of water. But a dripping faucet is a fraction of the cost of a burst pipe repair and water damage restoration.

5. Maintain Consistent Heat

Never turn your heat below 15°C, even when you are away. A weekend trip with the thermostat set to 10°C can result in frozen pipes by the time you return. Smart thermostats let you monitor and adjust remotely — worth the investment for any Ontario homeowner.

6. Disconnect Outdoor Hoses

Leaving a hose connected traps water in the outdoor faucet, which freezes back into the pipe and splits the interior line. Disconnect every hose, drain it, and store it indoors. Shut off the interior valve to outdoor faucets if your home has them, then open the outdoor faucet to drain any remaining water.

7. Know Where Your Main Shutoff Is

If a pipe does burst, every second counts. Know exactly where your main water shutoff valve is and how to operate it. In most Ontario homes, it is near the front foundation wall where the main line enters, often close to the water meter. Test it annually to make sure it turns freely.

The Cost of Being Unprepared

A single burst pipe can release 200+ litres of water per hour. In a typical Ontario home, that means flooded basements, ruined drywall, destroyed flooring, and mold growth within 48 hours. Insurance claims for burst pipe damage can be substantial — and that does not count the deductible, the inconvenience, or the items that insurance does not fully cover.

Prevention costs a fraction of that. Pipe insulation, caulk, and a smart thermostat are inexpensive investments. A Jumbo Protection Plan includes annual winterization checks as part of the membership. The math is not even close.