What to Do If a Hot Water Pipe Is Frozen

hot water pipe that’s frozen

During a Michigan winter, it’s not uncommon to find a hot water pipe has frozen. A pipe that freezes is in danger of cracking and causing a flood when it thaws (frozen water expands and puts extreme pressure on pipe walls). Most homeowners are inclined to call a plumber if there are signs of a frozen pipe, such as no water from a faucet or frost visible on exposed piping. But there are ways to fix frozen pipes without a professional.

If you take action immediately, you can prevent a frozen pipe from bursting. Many frozen pipes thaw on their own and certainly not all burst. Nonetheless, you have control over the situation. Here are some ways you can fix the problem and restore the pipe to its unfrozen state. To achieve this:

Open a Hot Water Valve

First, turn off the main water valve to take the pressure off the frozen pipe. Then, open multiple hot water outlets if possible (including the one closest to the frozen pipe). By opening faucets, water will have a path to flow as the pipe unfreezes. Steam will also need a place to go as heat is applied. As the pipe thaws, running water will accelerate the defrosting process. Therefore, it’s beneficial to have faucets running until the pipe is completely thawed.

Find the Frozen Pipe

If there’s no water, the affected pipe is most likely in an exterior wall. The most susceptible pipes include those in uninsulated areas like attics, basements, and crawlspaces. Also, look near cold air vents, cold concrete, or an outdoor valve or spigot. As a last resort, check outdoor pipes; while designed to keep standing water out, they can freeze.

Apply Heat to the Frozen Pipe

Converting ice to water requires applying heat. When applying heat directly to a pipe, it’s best to avoid using an open flame (lighter, blow torch, etc.), as it can burn flammable materials and start a fire. We also don’t recommend using space heaters. There’s a tendency to leave these unattended, which is a fire risk as well. 

However, safe and effective methods of applying heat to an undamaged frozen hot water pipe include:

  • Shut Off the Main Water Supply: If you don’t need water from that pipe or the house is a vacation home, wait until the weather warms up to turn it on again.
  • Use a Hair Dryer or Heat Gun: Run the heat source back and forth along the exposed section of the frozen pipe. Avoid direct contact between the device and the pipe; excess or uneven heating can rupture it. Metal pipes are more heat tolerant, but PVC pipes can be damaged at 140℉.
  • Use an Incandescent Light Bulb or Heat Lamp: A light source heats the air surrounding the pipe to help thaw it out. Don’t leave a heat lamp unattended. You can hang tarps or blankets to trap heat in a small area and speed up the process.
  • Wrap the Pipe In a Hot Towel: Soak the towel in hot water and wring it out before wrapping it around the frozen pipe. The towel will cool. To avoid it freezing on the pipe, replace it every five to 10 minutes. Keep replacing the towel until the pipe thaws.
  • Apply Electrical Heat Tape: Wrap a single layer around the length of the affected pipe and plug the tape into an outlet. The heating elements will warm the pipe just enough to melt the ice.

Tips for Unfreezing an Inaccessible Hot Water Pipe

If you can’t physically reach a hot water pipe that’s frozen, you may need to open the wall. Drywall can be cut with a keyhole saw or a utility knife. This is a more intrusive method, but it can prevent the pipe from bursting. Consider placing an access panel over the hole if the problem recurs. 

Other ways to thaw remote frozen pipes include:

  • Pour a tablespoon of salt down a drain, which allows ice to melt at colder temperatures.
  • Run a fan heater positioned to blow warm air into an external vent (or ductwork where the pipe runs alongside).
  • Turn up your central heating system to 75℉ to 80℉; radiant heat should warm wall and ceiling materials surrounding the pipe.

Call Hoover If a Hot Water Pipe Is Frozen

We have a team of licensed, experienced, and reliable plumbers who can quickly thaw and repair frozen pipes. Same-day service is available to help prevent burst pipes and water damage. For prompt help with a frozen hot water pipe in Clinton Township and surrounding areas, call Hoover at (586) 701-6127 or request service online.

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