Water expands when it freezes — with enough force to burst copper, PEX, or PVC. A burst pipe can flood a home in minutes, so preventing frozen pipes is one of the highest-value winter chores there is. Here’s how to protect your plumbing before the cold hits, and what to do if a pipe freezes anyway.
Which pipes freeze first
The most vulnerable pipes are the ones exposed to cold air:
- Outdoor hose bibs, pool lines, and sprinkler supply lines
- Pipes in unheated spaces: crawl spaces, attics, basements, and garages
- Pipes inside exterior walls with little insulation — including the ones behind kitchen and bathroom cabinets on outside walls
Protect pipes before winter
- Disconnect and drain outdoor hoses. A connected hose traps water in the faucet and the pipe behind it, which freezes and bursts the pipe inside the wall. Store hoses indoors, shut off the interior valve feeding each outdoor bib, then open the outdoor bib to let residual water drain. Leave the outdoor valve open through winter so any remaining water has room to expand.
- Drain pool and sprinkler lines per the manufacturer’s instructions. Never fill them with antifreeze unless the manufacturer specifically directs it — antifreeze harms people, pets, wildlife, and landscaping.
- Insulate exposed pipes. Pre-formed foam pipe sleeves are cheap, sold at any hardware store, and take minutes to install — measure your pipe diameter first for a snug fit. Insulate both hot and cold lines. Electric heat tape (heat cable) is the next step up for chronically cold spots; follow the manufacturer’s instructions exactly.
- Insulate the spaces, not just the pipes. Adding insulation to attics, crawl spaces, and basement rim joists keeps the ambient air around pipes warmer.
- Seal air leaks. Cold air streaming through gaps around pipes, vents, and foundations freezes pipes fast. Caulk and weatherstrip those openings.
Good habits during cold snaps
- Let faucets drip. In extreme cold, keep a pencil-thin stream of cold water running from the faucet farthest from where water enters the house. Moving water is far harder to freeze — and it relieves pressure buildup if ice does start forming.
- Open cabinet doors. Open the doors under kitchen and bathroom sinks on exterior walls so warm room air reaches the pipes. (Move household chemicals out of reach of children and pets first.)
- Keep the heat steady. Set the thermostat to the same temperature day and night during cold snaps — the few dollars of extra heat are nothing next to a burst pipe. If you’ll be away, leave the heat on at a minimum of 55°F.
- Keep garage doors closed if water lines run through the garage.
- Going away for an extended winter trip? Shut off the main water supply and drain the system (open the lowest faucet and flush toilets to empty tanks and bowls). With no water in the pipes, nothing can freeze and burst.
How to thaw a frozen pipe
If a faucet gives only a trickle or nothing at all, you likely have a frozen pipe — most often where the pipe runs along an exterior wall or enters through the foundation. Act quickly but carefully:
- Keep the faucet open. As the ice melts, flowing water helps melt the rest and gives the meltwater somewhere to go.
- Apply gentle heat starting from the faucet end and working back toward the frozen section: an electric heating pad, a hair dryer, a space heater kept well away from flammables, or towels soaked in hot water wrapped around the pipe.
- Never use an open flame — no blowtorches, propane heaters, or kerosene heaters. Besides the fire risk, sudden intense heat can burst the pipe.
- Check every faucet. If one pipe froze, others are probably frozen too.
- Once water flows at full pressure, inspect the thawed section for cracks or leaks before considering the job done.
If a pipe bursts
Shut off the main water supply immediately — know where your main shutoff valve is before winter — then call for professional help. A burst pipe is not a DIY repair for most homeowners: the damaged section needs to be cut out and replaced, and water damage needs fast attention to prevent mold.
America’s Service Plumber is a free matching service. We’ll connect you with licensed local plumbers in your area for free quotes on burst-pipe repair and winterization — no obligation. Get a free quote.
