When a Hidden Leak Is an Emergency
Water you can see spreading, such as a ceiling that is sagging or drips from a light fixture, is urgent. Turn off the main water valve, switch off power to the affected area if water is near fixtures, and call the 24/7 line.
A slow leak that shows only on the meter can wait for a same-day appointment when one is available, but it should not wait long. Water that escapes inside a wall or under a slab keeps damaging materials, and a leak that runs for weeks costs more than the repair.
Signs of a Leak You Cannot See
Meter keeps moving
Close every tap and appliance. If the meter dial still turns, water is going somewhere.
Higher water bill with no change in habits
A running toilet or a hidden pipe leak is often the cause.
Warm spot on the floor
A hot water line may be leaking under a slab or floor.
Sound of running water at night
Water moving in a quiet house means a leak or a stuck fixture.
Low pressure throughout the house
A leak on the supply side can reduce pressure at every tap.
Musty smell or stained drywall
Moisture inside a wall shows up as odor, staining or paint bubbles.
How Leaks Are Found, Method by Method
| Method | What it does | Used for |
|---|---|---|
| Meter and pressure test | Confirms a leak exists and whether it is on the supply side | First step on high-bill calls |
| Acoustic listening | Amplifies the sound of escaping water in pipes | Slab, wall and buried-line leaks |
| Thermal imaging | Shows temperature differences from wet or hot-water leaks | Walls, ceilings, radiant floors |
| Moisture meter | Measures moisture in building materials | Confirming where water has traveled |
| Line isolation | Closes sections of pipe to narrow where the loss is | Pinpointing which line is leaking |
Water Bill Jumped?
Call the 24/7 line. Dispatch will explain the first steps and whether a same-day appointment is open.
Ceiling and Wall Leaks
Water travels, so the stain on a ceiling is rarely directly under the leak. A plumber follows the moisture back toward the source, often with a meter or thermal camera, and opens only as much drywall as needed. The cause may be a supply line, a drain, a shower pan or an upstairs fixture.
If a ceiling is bowing, do not poke it, since pooled water can come down at once. Place a bucket, keep people out of the room and call.
Under-House and Crawlspace Leaks
In homes with a crawlspace or a basement, leaks often hide above the ceiling of the lower level or against the foundation. The city's plumbing guidance notes that plumbing above a crawlspace with a concrete floor is permitted and that concealed plumbing must be reachable by an access door or panel, which is why a good plumber looks for those panels first.
If the lower level is damp, check for a failed sump pump or a drain problem before assuming a supply leak. Our sump pump repair page covers that side of it.
Buried Line, Yard and Meter-Box Leaks
The water service line runs from the main in the street to the house. The City of Rolling Meadows owns that line up to the shutoff valve, and the homeowner owns it from the valve into the house, per the city's lead service line information. A leak on the city side is a Public Works matter, and one on the home side is yours.
Signs of a buried leak include soft or unusually green patches, a wet area near the meter box, and a meter that moves when everything is off. When a service line is damaged, see water service line repair for repair and replacement options.
Slab, Irrigation and Pool Leaks
A leak under a concrete slab can show up as a warm floor or a bill spike, and our slab leak repair page covers the repair methods. Sprinkler systems leak at valves and heads, and spring startup is a good time to check. Pool and spa leaks are a separate niche, so tell dispatch if that is your situation and we will say what we can do.
What Affects the Price
Detection is priced by the time and the methods needed. Locating a leak does not include the repair.
Insurance may cover water damage from a sudden leak but usually not the cost of finding or fixing a slow, long-running one. Check your policy. Want your real number? Call (847) 281-8626.
Sources and Local Rules Behind This Page
Plumbing work in Illinois is governed by the Illinois Plumbing Code, 77 Ill. Adm. Code 890, which municipal inspectors enforce, and the Illinois Department of Public Health licenses plumbers. The service line ownership and lead notes here come from the City of Rolling Meadows water pages and its 2025 water quality report, according to which the city has no known lead service lines.
We name these sources so you can check them yourself. Rules and phone numbers change, so confirm with the city office or the state before you rely on any detail for a permit or a purchase.
Common Questions
Yes. The emergency line is open 24/7. If water is actively spreading, shut off the main first, then call.
Turn off all taps and appliances and look at the meter. If the dial or the low-flow indicator still moves, water is escaping somewhere.
Leak detection typically uses meter tests, acoustic listening, thermal imaging and moisture meters. Dispatch can explain what a visit would use for your situation.
The City of Rolling Meadows owns the service line up to the shutoff valve, and the homeowner owns it from the valve into the house.
We aim to open as little as possible. The plumber explains what needs opening and why before you approve the price.
Yes. See commercial plumbing for how after-hours and multi-unit calls work.
Still not sure what you are dealing with? Call (847) 281-8626 and describe it to our dispatcher.