Every year, the first stretch of single-digit nights fills our dispatch board with the same call: a pipe burst in a wall or crawl space, and water is running somewhere it should never run. Most of those calls were preventable, and not with anything expensive — with habits that cost almost nothing.
Pipes freeze for one reason: standing water in a line that sits below freezing for long enough. In Chicago housing stock, the usual suspects are pipes in exterior walls (especially kitchen sinks on outside walls), uninsulated crawl spaces, garage ceilings with bathrooms above them, and the hose bibs nobody disconnected in October.
The checklist we use on our own houses
First, before the cold hits: disconnect garden hoses, shut the interior valve feeding each outdoor spigot, and open the spigot to drain it. A frozen hose bib is the single most common failure we see, and it is a five-minute fix in the fall.
Second, on nights below about 10°F: open the cabinet doors under sinks that sit on exterior walls so room air can reach the supply lines, and let the faucet farthest from your water meter run at a pencil-lead trickle. Moving water resists freezing, and the trickle costs pennies a night — drying out a flooded basement starts around $3,000.
Third, know where your main shutoff is before you need it. In most Chicago bungalows and two-flats it is a round gate valve or quarter-turn ball valve on the street side of the basement, near the water meter. Test that it actually turns — a seized valve during an active burst turns a bad night into a catastrophic one.
If a pipe freezes anyway
If a fixture stops flowing on a frozen morning, do not reach for a torch — we have rebuilt more than one wall because of an open flame on a pipe. Open the affected faucet, warm the suspect section with a hair dryer or a space heater aimed from a safe distance, and watch for the line to weep at fittings as it thaws. If you see any bulge or split, shut the main and call us before it lets go.
A burst line dumps roughly eight gallons a minute. That is why our emergency line is answered by a person at 2 AM in January — minutes genuinely matter.