What Happens When Your Pipes Freeze

As winter tightens its grip and outdoor temperatures plummet, indoor pipes are at risk of freezing. When water inside a pipe reaches 0°C (32°F) or lower, it can form ice, expand, and press against the pipe walls. This pressure can lead to cracks or bursts, especially if the pipe is already stressed by poor insulation or a long, narrow run.

What happens inside a frozen pipe: Ice creates a blockage that stops or slows water flow. Pressure builds upstream of the blockage, which can cause joints to loosen or the pipe to rupture. If a burst occurs, water can leak into walls, ceilings, or basements, causing mold, property damage, and expensive repairs. In some cases, the pipe may not burst immediately but may freeze repeatedly, weakening the material over time.

Common risk points: Exterior walls, crawlspaces, basements, and unheated rooms are typical cold spots. Pipes near uninsulated windows, careless attic spaces, or near exterior faucets are especially vulnerable. Short, exposed runs (like under sinks) are common sites for freezing if heat loss is high or airflow is poor.