PEX pipes are less likely to burst from freezing than copper or steel pipes because the plastic can stretch a little as water turns to ice. They can still crack or split after repeated freezes, and the fittings that connect PEX lines are often the weak point.
Why PEX Handles Cold Better
PEX is a flexible plastic tubing used in many newer homes and remodels. When water freezes, it expands. Rigid pipes have no room to give, so the pressure can split them. PEX can swell slightly and then return to its shape after thawing, which gives it some protection.
Where PEX Can Still Fail
- Fittings: brass or plastic connectors do not stretch, so ice pressure can crack them or push them apart.
- Repeated freezing: each freeze and thaw can weaken the tubing over time.
- Valves and fixtures: faucets, shut-off valves, and outdoor spigots connected to PEX can still crack.
- Long freezes: a line frozen solid for a long stretch can still split.
Freezing Still Stops Water
Even when PEX does not burst, a frozen line blocks water flow. You may lose water at one faucet or a whole bathroom until it thaws. Warm the area gently, open the faucet, and never use an open flame, since heat can damage plastic pipe quickly.
Protecting PEX Lines
Treat PEX like any other pipe in winter. Insulate lines in garages, crawl spaces, and outside walls. Keep the heat on when you are away. Let faucets drip on very cold nights. Seal drafts near where pipes enter the home.
After a hard freeze, check fittings and valves for slow drips once the water is flowing again. Leaks at connections can be small at first and easy to miss.
If a fitting or section has split, repairing the damaged connection before turning the water back on prevents a bigger leak. To find out which lines in your house are PEX and which are older pipe, you can have a plumber map out the lines in your house at (833) 603-1840.