How do I thaw frozen pipes safely?

Frozen pipes are a serious winter emergency in Ottawa, and acting quickly — but carefully — can prevent a burst pipe and thousands of dollars in water damage.

First, locate the frozen section. Turn on the faucet the pipe serves. If little or no water comes out, trace the pipe back toward exterior walls, unheated spaces (crawl spaces, garages, under cabinets on outside walls), or anywhere insulation may be lacking. These are the most common freeze points in Ottawa homes during our harsh winters.

Before you start thawing, turn off the main water supply valve. This is critical — if the pipe has already cracked from ice expansion, you won't know until the ice melts. Having the water off prevents a sudden flood when that happens. Your main shutoff is typically near the water meter, often in the basement.

Safe thawing methods include a hair dryer on low-to-medium heat, an electric heating pad wrapped around the pipe, or warm towels soaked in hot water. Work from the faucet end back toward the frozen section — this lets water and steam escape as the ice melts. Never use an open flame, propane torch, or heat gun. These can damage pipes, ignite nearby materials, and create a serious fire hazard.

In Ottawa, temperatures regularly drop to -20°C or colder, which means pipes in poorly insulated areas can freeze fast. If you can't locate the frozen section, or if it's inside a wall or inaccessible area, stop and call a plumber. Attempting to thaw pipes inside walls without proper equipment risks both fire and flood.

Once thawed, slowly turn the water back on and watch carefully for any drips or spraying water that would indicate a crack. Even a small crack can release hundreds of litres of water quickly.

For prevention going forward, consider adding pipe insulation sleeves to exposed pipes (available at any Ottawa hardware store), keeping cabinet doors open under sinks on exterior walls during cold snaps, and maintaining your home above 15°C even when away. If a section of your home repeatedly freezes, a licensed plumber can reroute or properly insulate that pipe run.

If you've had a freeze or want a professional assessment of your vulnerable pipes before next winter, Ottawa Pro Plumbing offers free consultations — it's much cheaper than dealing with a burst pipe cleanup.