Frozen Pipes in DeKalb: Prevention, Thawing and What to Do When One Bursts
DeKalb averages a January low around 13°F and has recorded 27 below. Those numbers do not just make pipes cold; they put the interior of an exterior wall cavity well below freezing for days at a time. Every winter we take the same calls, from the same five places in the house.
Where pipes actually freeze in DeKalb homes
- Exterior wall cavities. Especially second-floor bathroom supply lines in older homes, where the pipe was run up an outside wall because it was convenient in 1948.
- Rim joists and band joists. The gap between the foundation and the first floor is a notorious air-leak path, and pipes crossing it sit in outside air.
- Unheated garages and rooms above them. A bonus room over a garage has a floor cavity that is effectively outdoors.
- Crawl spaces and unconditioned additions. Porches enclosed later, four-season rooms and mudrooms are often plumbed without the insulation the rest of the house has.
- Hose bibs and sillcocks. A hose left connected over winter traps water in the sillcock body, which then splits inside the wall.
- Vacant properties. The single biggest cause of large losses in this city — a rental near campus with the heat turned off over break.
The prevention list, in order of value
- Disconnect every garden hose before the first hard freeze and drain the sillcock. This is free and prevents one of the most common failures we see.
- Keep any vacant or unoccupied property at 55°F minimum. Not off, not 45°F. If a tenant is leaving for break, put it in writing.
- Air-seal before you insulate. Cold air leaking into a cavity is what freezes a pipe; insulation alone just slows the heat loss. Foam and caulk at the rim joist does more than pipe sleeves.
- Insulate the pipes you cannot re-route, using proper closed-cell sleeves with the seams sealed rather than loose wrap.
- Open cabinet doors under sinks on exterior walls during a deep cold snap so room air reaches the pipe.
- Let a pencil-thin trickle run from the fixture farthest from the meter during extreme cold. Moving water is far harder to freeze, and it relieves the pressure that actually splits pipes.
- Know where your main shutoff is and verify it turns. Do this in November, not at 2am in February.
How to thaw a frozen pipe without making it worse
If a faucet gives you nothing and the weather has been cold, you likely have ice in the line.
- Open the affected faucet so melting water and steam have an escape route.
- Apply gentle, even heat starting at the faucet and working back toward the frozen section. A hair dryer, a heat gun on low, a space heater aimed at the wall or cabinet, or hot towels all work.
- Never use an open flame — a torch, a propane heater pointed at framing. It is a well-documented cause of house fires and it can also boil water inside a closed section and burst it.
- Stand ready at the shutoff. A pipe that split while frozen does not leak until it thaws. Have someone at the main valve while the line comes back.
If you cannot find the frozen section, if it is inside a wall you cannot reach, or if the line serves a whole floor, call us before applying heat.
When it bursts: the first five minutes
- Shut off the main. Clockwise until it stops. If it will not close, call the City of DeKalb Water Division at 815-748-2050 to have the curb stop shut.
- Open the lowest faucets in the house to drain pressure and slow the flow at the break.
- Cut power to the area at the breaker if water is near outlets, the furnace, the panel or the water heater — only if you can reach the panel without standing in water.
- Call us at (815) 849-0091. We answer 24 hours and will talk you through anything above that you have not managed.
- Photograph everything before you clean up. Your insurer will want it and it cannot be recreated later.
The thaw is the dangerous part
We take more burst-pipe calls in the days after a cold snap than during it. A pipe that split at 2am on the coldest night stays plugged with ice and leaks nothing. Three days later the temperature comes up, the ice clears, and water runs into a wall cavity while everyone is at work. If you had a fixture stop working during a freeze — even briefly, even if it came back — check that area carefully when it warms up.
What to do about the pipe that keeps freezing
A line that freezes twice will freeze again. The permanent answers, in order of preference: re-route it into conditioned space, air-seal and insulate the cavity properly, or as a last resort add self-regulating heat trace cable with a proper thermostat. We do all three, and we will tell you which one your particular run needs rather than selling you the easiest.
Quick answers
The commonly cited threshold is around 20°F outdoor temperature for pipes in unconditioned spaces, but it depends far more on exposure and duration than on a single number. A poorly sealed rim joist with a wind blowing through it can freeze a pipe at higher temperatures than a well-insulated cavity will at 5°F.
Not all winter — that is a lot of water on your City of DeKalb bill. Do it during genuine cold snaps, on fixtures served by vulnerable runs, and stop when the weather moderates. It is a tactic for extreme conditions, not a season-long policy.
Illinois policies commonly cover sudden and accidental water discharge and the resulting damage. Many exclude damage caused by freezing if the property was unoccupied and reasonable heat was not maintained, which is exactly why the 55°F rule for vacant properties matters beyond the plumbing.
More leak guides
The 30-minute meter test that tells you whether water is escaping, and whether it is inside the house or underground.
Eight causes of a sudden bill spike, ordered from the cheapest fix to the most serious.
Four causes, four different fixes, and how to tell them apart before spending money.
Leak line, answered 24 hours
(815) 849-0091Call nowOne call does it. We work out what is likely wrong on the phone, quote before we come out, and book you in on the same call.