how long does it take to unfreeze pipes

It usually takes about 30–45 minutes of steady, safe heat to unfreeze most household pipes, but the real answer depends a lot on where the pipe is and how cold it is outside.

How Long Does It Take to Unfreeze Pipes? (Quick Scoop)

Typical Thaw Times

For many homes in winter 2025–2026, plumbers and insurers are giving similar ballpark ranges for thawing times.

• Exposed indoor pipes (easy access):
  Around 30–40 minutes of continuous heat (space heater, heat tape, or hair dryer used safely) is often enough.

• Enclosed pipes (inside walls, cabinets, crawlspaces):
  Can take 1–2 hours or more , because heat has to work through drywall, cabinets, or insulation.

• Underground or exterior lines (yard supply lines, buried mains):
  Can take many hours to days , and in some cases weeks if you just “wait for a warm spell,” especially in long deep runs of pipe.

If you do nothing and simply wait for warmer weather, frozen pipes may thaw in a few hours to several days , depending on how long the temperature stays below freezing and how well the pipes are insulated.

What Actually Affects Thaw Time?

Several factors change how long it takes to unfreeze pipes.

• Location of the pipe
  • Basement / utility room pipes thaw fastest.
  • Pipes in exterior walls, crawlspaces, and attics thaw slower.
  • Buried or outdoor pipes thaw slowest.
• Current temperature
  • Around freezing (30–32°F / about 0°C): thawing is much quicker.
  • Deep cold (near or below 20°F / about −6°C): pipes can stay frozen for as long as the cold snap lasts.

• Insulation and airflow
  • Lightly insulated pipes near warm rooms thaw faster.
  • Pipes behind thick insulation or in dead-air spaces may barely warm up.
• Length and material of the pipe
  • Longer runs and larger-diameter pipes take more time to warm.
  • Metal (copper, steel) conducts heat faster than plastic, but also loses it faster to very cold air.

A simple example: an exposed copper pipe in a heated basement might be running again in under an hour, while a frozen outdoor supply line in a sub-zero cold snap might still be solid after several days if you don’t actively warm it.

Safe Ways to Speed Up Thawing

Professionals emphasize that how you thaw matters as much as how long it takes, because bad techniques can crack pipes or start fires.

1. Prep and safety checks

1. Shut off the main water supply if you suspect a pipe may already be cracked, then open nearby faucets to relieve pressure.

2. Locate the frozen section by checking where water stops flowing or where pipes feel very cold or frosty to the touch.

2. Safe heat methods

Use gentle, indirect heat and keep it constant rather than blasting high heat.

• Hair dryer on low/medium , moving slowly along the pipe.
• Space heater in the room (kept at a safe distance from combustibles).
• Heating pads or electric heat tape rated for pipes.

Common safety warnings:

• Do not use open flames (propane torches, lighters, etc.).
• Do not pour boiling water down drains to thaw pipes; it can refreeze further down, create steam surges, and raise burst risk.

• Keep electrical devices away from pooled water to avoid shock.

When Pipes Might Thaw On Their Own

If temperatures are rising and you’d rather not intervene, frozen pipes will usually thaw as the air warms , but this strategy has real risks.

• In a mild cold snap that turns above freezing during the day, pipes may thaw naturally over several hours.
• In sustained cold (around 20°F / −6°C or below), pipes can stay frozen for the entire cold spell and become more likely to burst as pressure builds.

Plumbing and insurance sources strongly recommend not just “waiting it out,” because the longer a pipe stays frozen, the more likely it is to crack and flood the home once it finally thaws.

Quick FAQ Style Recap

• How long does it take to unfreeze pipes with active heat?
  Usually 30–45 minutes for accessible indoor pipes; longer for hidden or underground lines.

• How long if I just wait?
  Anywhere from hours to weeks , depending on the weather, pipe location, and insulation.

• Can pipes thaw overnight?
  Yes, especially if temps rise above freezing and the pipe is indoors, but it’s a gamble with burst risk.

• When should I call a pro?
  • You can’t find the frozen spot.
  • You see bulging or cracks.
  • Thawing hasn’t worked after an hour or two on an enclosed or critical line.

Information gathered from public forums or data available on the internet and portrayed here.