Preventing Frozen Pipes in Central Illinois

How cold Decatur gets

Decatur's average January low is about 17°F, and the county's record low is −25°F, set in February 1905 (Wikipedia: Macon County, Illinois). The Illinois State Climatologist keeps the state's temperature records and seasonal summaries (Illinois State Climatologist). The National Weather Service office in Lincoln issues cold and wind chill alerts for Macon County (National Weather Service Lincoln, IL). Wind matters too: a strong wind pulls cold air through gaps in walls, rim joists and crawlspace vents.

Why pipes burst

Water expands as it freezes. An ice plug forms, and the water trapped between the ice and a closed faucet has nowhere to go. Pressure builds until the pipe splits, often somewhere other than the frozen spot itself. When the ice melts, the water flows out.

Where pipes freeze

• Exterior walls, especially kitchen sink lines.
• Crawlspaces under additions, porches and sunrooms.
• Attached garages.
• Near basement rim joists where air leaks in.
• Outdoor hose bibs and sprinkler lines.

Fall checklist

1. Disconnect hoses and close interior shut-offs to non-frost-free hose bibs, then drain them.
2. Blow out or drain irrigation lines.
3. Insulate exposed pipes in crawlspaces and garages with foam sleeves.
4. Seal gaps around pipes where they pass through exterior walls and rim joists.
5. Close crawlspace vents for the winter if the design allows.
6. Check that the sump discharge line drains and will not freeze.
7. Find and test the main shut-off.

During a cold snap

• Open sink cabinet doors on exterior walls to let warm air in.
• Let a faucet on a vulnerable line drip.
• Keep the thermostat steady day and night.
• Keep the garage door closed.

The National Weather Service's winter safety pages cover pipes along with other cold-weather risks (National Weather Service, cold weather safety).

Vacant homes and travel

If you are away in winter, keep the heat on at a safe setting and ask someone to check the house. For a house that will be empty for a long time, shutting off the water and draining the lines is the safest route. Smart leak sensors and temperature alerts can warn you early.

If a pipe freezes or bursts

Open the faucet, apply gentle heat, and never use an open flame. If you see a split, close the main shut-off. University of Illinois Extension has information on cleanup after water damage (University of Illinois Extension). See frozen pipe repair.

Permanent fixes

A line that freezes every year should be moved into the heated envelope, insulated properly or protected with pipe-rated heat cable. Frost-free hose bibs end outdoor-faucet freezes.

Related pages: frozen & burst pipe repair, leak detection & repair, toilets, faucets & fixtures, and what shapes an estimate.

Sources: Illinois State Climatologist; National Weather Service Lincoln, IL; National Weather Service, cold weather safety; University of Illinois Extension.