How to Prevent Frozen Pipes (and What to Do If They Freeze)

Why pipes freeze and burst

Water expands as it freezes, and that expansion creates enormous pressure inside a pipe. The pipe often bursts not at the frozen spot itself but in the section between the ice blockage and a closed faucet, where pressure builds. The pipes most at risk are those in unheated areas — basements, attics, garages, crawl spaces — and those running along exterior walls. Knowing where your vulnerable pipes are is the first step to protecting them.

Prevent them before the cold

• Insulate exposed pipes in unheated areas with foam pipe sleeves or insulation.
• Seal drafts near pipes where cold air gets in, around rim joists, vents, and gaps.
• Disconnect and drain outdoor hoses and shut off and drain outdoor faucets before winter.
• Keep the heat on and never let your home drop too low, even when away — a minimum temperature protects pipes.
• Know where your main shutoff is so you can act fast if a pipe bursts.

During a hard freeze

When temperatures drop sharply, take extra precautions. Let cold-vulnerable faucets drip slightly; moving water is far less likely to freeze, and a trickle relieves pressure. Open cabinet doors under sinks on exterior walls so warm room air reaches the pipes. Keep the thermostat at a consistent temperature day and night rather than lowering it overnight. If you will be away during a freeze, keep the heat on and consider shutting off and draining the system.

If a pipe freezes but hasn't burst

If a faucet produces only a trickle, you likely have a frozen pipe. Keep that faucet open so water can flow as the ice melts. Apply gentle heat to the frozen section using a hair dryer, a heating pad, or towels soaked in warm water, working from the faucet end toward the blockage. Never use an open flame or torch — that is a fire hazard and can damage the pipe. If you cannot locate or reach the frozen section, or it does not thaw, call a plumber.

If a pipe bursts

Act immediately: shut off the main water supply to stop the flooding, which is why knowing your shutoff location matters so much. Then open faucets to drain remaining water and reduce pressure. Move belongings away from the water, document the damage with photos for insurance, and call a plumber. Sudden pipe bursts are often covered by homeowners insurance, so contact your insurer, but stopping the water first is what limits the damage.

When to call a professional

Call a plumber if you cannot find or safely thaw a frozen pipe, if a pipe has burst, or if you want vulnerable pipes properly insulated before winter. Preventive work by a professional is far cheaper than emergency repairs and the water-damage cleanup that follows a burst. If freezing is a recurring problem, a plumber can identify and fix the underlying vulnerability.

Quick recap

• Insulate pipes in unheated areas, seal drafts, drain outdoor faucets, and keep the heat on.
• During a hard freeze, let vulnerable faucets drip and open cabinets to reach pipes with warm air.
• To thaw a frozen pipe, keep the faucet open and apply gentle heat — never an open flame.
• If a pipe bursts, shut off the main water immediately, then drain, document, and call a plumber.

Frozen pipes are one of winter's most preventable disasters. Insulate and drain vulnerable pipes before the cold, let faucets drip during a hard freeze, thaw any frozen pipe gently, and above all know where your main shutoff is so you can stop a burst fast. A little preparation protects your home from a very expensive flood.