Frozen Pipe Risk Checker

Enter your ZIP to get your area's frost line depth and freeze-day exposure — the two factors that determine how vulnerable your pipes are.

Why do frost line and freeze days both matter?

Frost line depth tells you how far below grade water lines must be buried to avoid freezing — required by IPC Table 301.5. Freeze days tell you how often your above-grade pipes (in crawl spaces, exterior walls, unheated garages) face dangerous ambient temperatures. A home in Memphis (10" frost line, 35 freeze days) has far lower risk than a home in Minneapolis (72" frost line, 140 freeze days) even if both have similar insulation.

What is the critical temperature for frozen pipes?

Pipes typically begin freezing when the ambient air surrounding them drops below 20°F for a sustained period. Heat tape and foam insulation shift the threshold — a ¾" pipe wrapped in R-4 foam can resist ambient temps down to approximately 0°F before freezing risk becomes critical. The checklist items at each risk level reflect these real-world thresholds.

What should you do if a pipe freezes?

1. Shut off the main water supply immediately — a thawed burst pipe releases 2–8 gallons per minute.
2. Open a faucet on the affected line to relieve pressure as the ice thaws.
3. Apply gentle heat (hair dryer, heating pad) starting at the faucet end and working toward the frozen section. Never use open flame.
4. If you can't locate the frozen section or the pipe has already burst, call a licensed plumber. Emergency burst-pipe service typically runs $250–600 for the service call, plus materials and drywall repair.

Data sources: methodology page.