How to Thaw a Frozen Pipe Without Bursting It or the House

The morning after a hard North Texas freeze, a tap that gives nothing or a thin trickle usually means a section of pipe has frozen. That pipe may or may not have split. Water expands as it freezes, and if the ice had nowhere to go, the pipe wall gave. You cannot tell which from the tap. That uncertainty is why the sequence below matters more than the thawing method.

Before you apply any heat

1. Find the main shutoff and make sure you can close it quickly. If a split is hiding in the ice, it will start flowing the moment the ice clears, and you want to be one turn away from stopping it.
2. Open the affected tap, both hot and cold. This relieves pressure between the ice and the tap, gives melt water somewhere to go, and lets you see the moment flow returns.
3. Locate the frozen section. Trace the pipe from the dead tap back toward the supply. Frozen sections are usually where the pipe passes through an exterior wall, an unheated garage, a crawl space or the attic, or where it feeds an outdoor hose bib. Frost on the pipe, or a section that feels colder than the rest, is the spot.
4. Look at that section for a split, a bulge or a wet patch before thawing. If you can see damage, stop: close the main, and call (469) 338-5533 rather than thawing a pipe you know is broken.

Safe ways to thaw

• A hair dryer on high, moved along the pipe starting from the tap end and working toward the frozen section. This is the tool we recommend for most homeowners. It is slow and that is the point.
• Towels soaked in hot water wrapped around the pipe and re-soaked as they cool.
• A heating pad or electric heat tape wrapped around the pipe, on a low setting.
• A space heater in the room or cabinet, with the cabinet doors open, if the pipe is inside a wall you cannot reach directly.
• For a pipe in the attic or a wall, raising the temperature of the whole house a few degrees and opening cabinet doors on exterior walls is often what does it.

What to watch for as it thaws

Stay with it. When flow returns at the tap, watch and listen for water anywhere it should not be: a drip from a ceiling, a hiss in a wall, water on the garage floor. If you see or hear any of that, close the main. A split that only shows once flow returns is the most common way a frozen pipe becomes a burst pipe, and it usually happens in the first minute.

If you cannot find the frozen section

Turn the heat up, open every cabinet on an exterior wall, open the attic hatch so warm air can rise into the attic, and leave the affected tap open a trickle. In most cases the section thaws on its own as the house warms. If the outdoor temperature stays below freezing for days, as it did in some recent winters, the pipe may not thaw on its own and the risk of a split rises with every hour it stays frozen. That is when to call; we have thawing equipment that reaches pipes you cannot.

Once the water is back

Check every fixture in the house, not just the one that was dead. Look at the water meter with everything off; a moving meter means water is escaping somewhere. Then deal with the reason it froze. A pipe that froze once will freeze again in the next cold snap unless it is insulated, rerouted, or the air leak that let cold reach it is sealed. Fixing that in February is the difference between a story and a habit.

Family-owned in Rockwall, licensed and insured, and we answer around the clock during freeze events. TX Master Plumber TXM11693. (469) 338-5533.