Slab Leak Detection in Fort Worth

Fort Worth Leak Detection is a referral and matching service. We connect you with independent, TSBPE-licensed local plumbers; we don’t perform the work ourselves. This page explains what a slab leak is, how to check for one yourself, and how a licensed plumber confirms and pinpoints it, so you know what to expect before anyone shows up.

What a slab leak actually is

A “slab leak” is plumbing jargon for a leak in a pipe that runs beneath or inside a concrete foundation. It can be on the hot side, the cold side, or a drain line. Hot water lines tend to leak more often because they expand and contract with every use, and that movement rubs pipe against concrete, gravel, or other pipes. North Texas clay soils add stress of their own: the ground swells when wet and shrinks when dry, and the slab and the pipes under it move with it.

Common causes include pinhole corrosion in copper, abrasion where a pipe touches rebar or concrete, poor joints from original construction, and shifting soil. None of these are anyone’s fault in particular. They’re just what happens to buried pipes over time.

Signs worth taking seriously

• A higher water bill with no change in habits, especially one that keeps climbing month to month.
• A warm or hot spot on the floor, often noticed barefoot on tile, which can point to a hot water line.
• The sound of running water when no faucet, toilet, irrigation, or appliance is running.
• Damp or warm carpet, swelling wood floors, or loose tiles away from any bathroom or kitchen.
• A water heater that seems to run constantly.
• Lower water pressure throughout the house.
• Musty smells or mildew along baseboards with no obvious source.
• New cracks in walls or flooring, which can happen when water washes out soil under part of the slab. Cracks have many causes, so they’re a clue, not proof.

One sign on its own doesn’t confirm anything. Two or three together, especially a high bill plus a warm spot or running-water sound, are a good reason to have the system tested.

A simple meter test you can do today

Before you call anyone, you can check whether water is moving through your system when it shouldn’t be:

1. Turn everything off. Faucets, showers, dishwasher, washing machine, ice maker, irrigation, pool fill. Make sure no toilet is refilling.
2. Find your water meter. In most North Texas cities it sits in a box near the street. Lift the lid carefully (watch for insects).
3. Watch the leak indicator. Many meters have a small triangle or star that spins when any water flows. Or write down the reading and check again in an hour without using water.
4. If it moves, water is going somewhere. Next, turn off your home’s main shut-off valve. If the meter stops, the leak is inside the house (possibly under the slab). If it keeps moving, the leak may be in the yard line between the meter and the house. See our water line and sewer leak page.

A running toilet is the most common false alarm, so rule that out first. To check, put a few drops of food coloring in the tank. If color shows up in the bowl without flushing, the flapper is leaking.

How a plumber pinpoints a slab leak

Leak detection is usually done in two stages: first confirm that there’s a leak and which line it’s on, then narrow down where it is so the repair opening is as small as possible.

• Pressure testing and line isolation. The plumber shuts off sections of the system and checks which line loses pressure. This tells them whether it’s the hot side, cold side, or a specific branch.
• Acoustic listening. Water escaping a pressurized pipe makes noise. Ground microphones and amplifiers help locate the loudest point through concrete and flooring.
• Thermal imaging. On hot water lines, an infrared camera can show the heat pattern of escaping water under the floor.
• Tracer gas. For hard-to-find leaks, a safe gas mixture is pushed into the drained line and detected where it comes up through the slab.
• Camera inspection and drain testing for drain and sewer lines, which leak differently from pressurized supply lines.

Good detection is what keeps a repair affordable. Opening the floor in the wrong spot costs time, concrete work, and flooring. Ask the plumber how they’ll locate the leak and how close they expect to get before any concrete is cut.

What detection usually costs

Leak detection is usually a separate, paid service. National cost guides put typical slab leak detection at roughly $150–$400, with complex homes running higher (Angi, 2026). Prices in Fort Worth vary by company, the size of the home, and whether it’s after hours. Always ask for the detection fee up front, and ask whether any of it is credited toward the repair. See our FAQ on costs and insurance for more.

After the leak is found

Once the plumber knows where the leak is, you’ll usually choose between three paths: a spot repair or tunnel to fix the pipe where it sits, a reroute that abandons the leaking line and runs a new one through walls or the attic, or a whole-house repipe if the pipes are old and failing in several places. If water has already soaked flooring or drywall, see water damage after a leak.

Checking the plumber you’re matched with

Plumbing in Texas is licensed by the Texas State Board of Plumbing Examiners. You can look up any plumber’s license status on the TSBPE public license search. It’s a quick step, and we encourage it no matter who you hire.

Common questions