KANSAS CITY GUIDE

Signs that point to a slab leak in a Kansas City home

A slab leak is water leaving a line under a concrete floor. It is a specific failure, and it is easy to accuse the slab of every warm tile and every high water bill. Many houses in this metro have basements or crawlspaces, where a leak is often visible once you look. Use the clues below to decide whether an under-slab search is even the right kind of search, and do not open the floor to settle a guess.

By Mike M · Sources checked October 6, 2026 · How we write these guides

Not every house has a slab

Start with the foundation you actually have. If there is a basement, walk it. Supply lines, a water heater, and the main shutoff are often visible, and a wet ceiling down there is coming from above, not from under a slab that is not there. If there is a crawlspace, the leak may be in that space, which is harder to reach safely but is still not a slab leak. A slab-on-grade house, where the first floor is concrete and there is no basement under the living area, is the layout where an under-floor supply line is even a candidate.

Parts of the metro also sit on soils that move as they wet and dry. That movement can stress buried lines. It does not mean your house has a slab leak this month. It means a plumber should hear the foundation type and the soil story as background, not as a diagnosis you already paid yourself to believe. The leak guide covers stains, meters, and the difference between a ceiling ring and a hidden loss.

Clues that belong together

One clue is a hint. Several clues that agree are a reason to call. The useful cluster looks like this: the meter moves when every fixture is off, you sometimes hear water running inside the house with nothing on, a particular stretch of floor is warmer than the rooms around it, and pressure has fallen at more than one cold or hot fixture. Hot-line leaks warm the floor. Cold-line leaks usually do not. A water bill that jumped without extra people in the house belongs in the same cluster if you have ruled out a running toilet and a hose left on.

None of those, alone, is a slab leak. Together they justify a plumber who can listen and pressure-test, especially in a slab house with no wet basement to inspect. The low pressure guide helps you separate a single clogged aerator from a whole-house drop before you blame the floor.

Clues that usually are not a slab leak

A brown ring on a ceiling is water from above that ceiling: a tub, a supply in the floor or wall of the room overhead, or a roof. It is not fixed by opening the slab. Condensation on a cold pipe in humid weather wets the outside of a line you can see. The summer plumbing guide shows how to tell that bead from a joint that keeps dripping. Groundwater in a basement after a storm, with a sump that should have run, is a different system again.

A toilet that refills every few minutes is often a flapper or a fill valve in that tank. Check that before you fund an under-slab search. A single shower that lost pressure while the kitchen is strong is a fixture problem. Slab stories grow when someone skips the boring checks. Do the boring checks. They are cheaper than concrete.

What a meter can and cannot prove

With every faucet off, no ice maker calling for water, and no irrigation running, watch the meter. Many meters have a small triangle or a dial that turns if water is moving. If it moves, water is going somewhere on your side of the meter. Confirm how your meter displays that with the utility, because meter brands differ across the metro. If it does not move, a slab leak large enough to matter is unlikely right now. A tiny seep can sit below what you can see. It is not a reason to cut the floor tonight.

How a plumber looks without a jackhammer

A careful company will pressure-test sections, listen with detection gear, and use the meter with you. They should be able to say which side of the system they suspect and why. Cutting concrete is a later step, after a location, not the method of location. Ask where the water will go when they open the line, and ask how they will patch the pipe they find — a repair coupling in the floor, a reroute through a wall or ceiling, or a longer repipe. Those are different jobs and different prices. The cost guide is about that difference. Access under a finished floor is the expensive part, and you should hear it described before the saw starts.

What to authorize, and what to delay

Authorize the test and the location first if the house is stable. Authorize an emergency shutoff and a temporary repair if water is damaging finishes or the meter is spinning hard enough that you should not wait. Do not authorize a whole-house repipe as the first sentence of the visit. If the located leak is one fitting under one room, a reroute of that run may be reasonable, and a full repipe may be a separate bid you collect in daylight. The questions to ask before hiring include who is licensed for your side of the state line and what the written scope must contain.