Crawlspace pipes frozen

Symptoms

• No water or reduced flow at fixtures fed by crawlspace pipes
• Crawlspace access panel or vents left open during cold weather
• Visible frost on pipes if you can see into the crawlspace
• Problem coincides with a cold snap

Likely causes

• CommonUninsulated pipes in a vented, unconditioned crawlspaceCold outside air circulating through vents can bring crawlspace temperatures well below freezing.
• CommonOpen crawlspace vents left uncovered during winterMany recommend closing foundation vents during freezing weather, and this is often overlooked.
• PossiblePipe insulation missing, damaged, or improperly installedEven where insulation exists, gaps or thin coverage can leave pipes vulnerable.
• Less commonExtended power outage disabling heating in a conditioned crawlspaceIf the crawlspace relies on conditioned air from the house, a heating outage can allow it to freeze.

What to do

1. If accessible, check the crawlspace for open vents and close them during freezing weather (reopening in warmer months for ventilation).
2. Locate the frozen section by checking where flow stops for specific fixtures, then visually inspecting that area if you can safely access it.
3. Apply gentle heat with a hair dryer or heat lamp positioned safely away from flammable materials, working from the faucet end toward the blockage.
4. Keep a faucet open slightly during thawing to let water flow and relieve pressure as the ice melts.
5. Once thawed, carefully inspect the pipe for any cracks or splits before considering the repair complete.
6. Add or improve pipe insulation throughout the crawlspace, focusing on any pipes near vents or exterior walls.
7. Consider heat tape for persistently vulnerable sections, and keep the crawlspace access panel closed and sealed during winter.

Tools and parts

• Hair dryer or heat lamp
• Flashlight

When to call a pro

Call a plumber if you can't access the frozen section safely or find cracking once thawed.

Safety