FAQ

Typically an estimated $150 to $400, with the repair as a second, separate quote. Where the buried service line is hard to reach, an estimated $300 to $800 is realistic. Nobody has verified a Mount Prospect average, so none is printed here.

Start with which water it is. With every fixture off, watch the low-flow dial on the basement meter: turning means a leak past it. If it is still and water keeps appearing, rain points at the ground, the floor drain at the sewer, and the wall where the service enters at your buried line.

Usually something past the meter keeps running, and a toilet flapper that no longer seals is a common quiet one. Compare the dials with the reading on the bill. A leak on the buried line before the meter never shows on the bill at all.

Here the line runs the other way round. The village owns the main and the line out to the B-box; the owner owns it from the B-box to the meter inside the house, and everything after. Illinois American Water customers should ask that utility how its line is split.

Yes, when the meter shows water moving and nobody can see where, because a precise mark keeps the repair small. Less so when the water follows rain. And if your line is on the village's lead and galvanized map, replacing it may beat pinpointing a leak on it.

Because much basement water never came from a pipe. Groundwater pushes through where wall meets floor after heavy rain, and the village's combined sewers, the oldest from the 1920s, can back up through a floor drain in a storm.

For the repair, yes, and in this state that plumber is licensed by the Illinois Department of Public Health. Locating comes first when the leak is hidden, because it tells the plumber where to cut, and replacing a water service needs a village permit.

Listening, imaging and testing. Acoustic gear hears water escaping under pressure, a thermal camera shows warm or wet patches, and pressure tests or tracer gas — five percent hydrogen in nitrogen — confirm which line is failing.