A slab leak = water pipe break under your concrete foundation. The water escapes into the soil or rises up through the slab.
Water escaping under pressure makes a sound — a hiss or rumble. The acoustic listening device picks up this frequency through the concrete, even when you can't hear it yourself.
Hot water leaking under the slab warms the concrete above it. A thermal camera sees temperature differences invisible to the eye — orange/red patches reveal where heat is escaping.
The plumber shuts off all water and pressurizes the pipe to a set PSI. If pressure drops over time without any water being used — there's a leak. Isolating hot vs cold confirms which line.
A waterproof camera on a flexible cable is fed into the sewer cleanout. The tech watches live video of the inside of the pipe — seeing cracks, root intrusion, collapsed sections, or offset joints under the slab.
Click each step to see what happens