A careful thawing sequence
Work from the faucet back toward the frozen section so melted water has somewhere to go.
Find the main shutoff first
Before applying any heat, locate the main valve and make sure it turns. If the pipe has already split, water will start flowing as soon as the ice softens, and the valve is the only thing that stops it.
Open the affected faucet
Turn both hot and cold handles on the fixture that stopped working. An open faucet relieves pressure and gives you a signal: when water starts to trickle, the plug is melting.
Trace the likely frozen section
Follow the pipe from the faucet toward the nearest exterior wall, unheated garage, crawlspace or cantilevered floor. Frost on the pipe, a bulge or a spot that feels much colder than the rest are clues.
Apply gentle, steady heat
A hair dryer, a heating pad, warm towels or a space heater placed at a safe distance all work. Start nearest the faucet and move back. Keep the heater away from curtains, boxes and insulation, and never leave it unattended.
Watch for water where it should not be
As flow returns, have someone check the ceiling below, the base of the wall and the basement. A hissing sound or a new drip means the pipe cracked; close the main right away.
Keep the area warm afterward
Leave cabinet doors open and keep a slow drip running until the cold breaks. A pipe that froze once is likely to freeze again in the same spot.
Handle it yourself, or call a plumber now?
Many households can safely thaw an accessible line. Some situations are better left to a licensed plumber from the start.
Reasonable to try
- The frozen section is exposed under a sink or in an unfinished basement.
- You can reach the main shutoff and it turns freely.
- Only one fixture has stopped flowing.
- There is no visible bulge, split or water on the floor.
Call a plumber
- The ice is inside a finished wall or ceiling you cannot reach.
- Several fixtures or the whole house have lost water.
- The pipe is visibly swollen, cracked or already dripping.
- The main shutoff is stuck, missing or buried under storage.
Why the whole-house symptom matters
When a single faucet stops, the ice is usually close to that fixture. When the entire house loses water, the freeze may be at the point where the service line enters, often a basement wall or crawlspace near the front of the house. In some cases the problem is even outside, in the line between the curb stop and the foundation. That calls for a plumber, and possibly a conversation with the water provider.
Plumbers can use equipment designed for this, such as electric pipe-thawing machines for metal pipe, that a homeowner should not improvise. Ask what type of pipe they found and whether it should be rerouted or insulated so the same section does not freeze next winter.
Common questions
- Is it safe to thaw PEX or plastic pipe with a hair dryer?
- Gentle heat from a hair dryer held at a distance is commonly used, but plastic pipe can be damaged by high heat. Keep the dryer moving and never use a heat gun or flame on plastic.
- Should I turn the water off before thawing?
- Many plumbers suggest knowing where the valve is and keeping it within reach rather than closing it first, because flow is how you know the ice has cleared. If you see signs of a split, close it immediately.
General information for Denver, not a quote or professional advice. In an emergency, call 911.