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Prevention

Why Pipes Freeze and Burst in Winter, and How to Prevent It

How Illinois winters cause frozen and burst pipes, which pipes are most at risk, and a 2026 prevention checklist to keep your plumbing safe through the cold.

Updated June 9, 2026·6 min read·By the IllinoisPlumbingDirectory editorial team

Illinois winters are hard on plumbing. A cold snap can freeze an exposed pipe overnight, and the damage often appears as flooding once it thaws. Understanding why pipes burst makes prevention simple, and it can save you from one of the most expensive home repairs there is.

1

Why frozen pipes actually burst

It is a common myth that the ice itself splits the pipe. The real cause is pressure.

The pressure, not the ice

As water freezes it expands. Once an ice blockage forms, continued freezing pushes water toward a closed faucet, and the pressure between the blockage and the faucet keeps climbing until the pipe fails, often far from the ice itself.

This is why a dripping faucet helps. An open path relieves the pressure that would otherwise burst the pipe.

2

Which pipes are most at risk in Illinois

Pipes in heated, interior spaces rarely freeze. The danger lives in the cold corners of the house.

  • Pipes along exterior walls with little insulation
  • Unheated basements, crawlspaces, attics, and garages
  • Outdoor hose bibs and sprinkler supply lines
  • Pipes near drafts from rim joists, vents, or gaps
  • Vacant or under-heated rooms and vacation homes
3

Prevent frozen pipes

Work through this list before the first hard freeze, and revisit it during extreme cold.

  1. 1Insulate exposed pipes with foam sleeves, especially in garages and crawlspaces.
  2. 2Let a faucet drip during deep cold on pipes that run through cold areas.
  3. 3Open cabinet doors under sinks so warm room air reaches the pipes.
  4. 4Keep the heat at 55 degrees or higher, even when away.
  5. 5Disconnect garden hoses and shut off and drain outdoor spigots before winter.
  6. 6Seal drafts near pipes with caulk or insulation.
4

If a pipe freezes but has not burst

Thaw gently, never with an open flame

Open the faucet so water can flow as the ice melts. Apply gentle heat with a hair dryer or a space heater kept away from anything flammable. Never use a blowtorch or open flame, which can damage the pipe and start a fire.

Start heating closest to the faucet and work back toward the blockage. If you cannot reach the frozen section or it will not thaw, call a plumber before it bursts.

5

If a pipe bursts

Speed limits the damage. Every minute the water runs adds to the cleanup.

  1. 1Shut off the main water valve immediately.
  2. 2Open faucets to drain the remaining water in the lines.
  3. 3Move belongings away from the water and document the damage for insurance.
  4. 4Call a licensed plumber to make the repair.

Our full plumbing emergency guide walks through every step, and you can find pipe repair pros in Illinois by city when you are ready.

6

Before you travel in winter

An empty house during a cold snap is the classic burst-pipe scenario.

Pro tip

Leave the heat set no lower than 55 degrees, shut off the main valve if you will be gone for a while, and ask someone to check the home during extended trips. If your basement relies on a sump pump, confirm it is ready using our sump pump maintenance guide.

Frequently asked questions

Sources & references

  1. Winter Storms and Extreme Cold: Frozen Pipes · Ready.gov (FEMA)
  2. IDPH Plumbing Program · Illinois Department of Public Health
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