How We Pinpoint a Broken Drain Under a Slab Without Tearing Up the Whole Floor

By the licensed master plumbers at Honest Choice Plumbing · TX Master Plumber License M-44120 · Published October 1, 2026

Walking the floor with a locator to find the camera head under the slab.

Most homes in North Texas sit on slab foundations, which means the drain lines run under the concrete. When one breaks, the big question is where. The answer decides whether you open a small square of floor or tear up a whole room.

Step 1: Run a camera down the line

A sewer camera goes into the drain through a cleanout or a fixture. We push it down the line while watching the screen until we reach the problem: a crack, a break, roots, a sag, or a separated joint.

Step 2: Locate the camera head from above

The camera head has a small transmitter in it. With the camera parked at the problem spot, we walk the floor above with a locator. The signal peaks directly over the camera head, and the locator also shows how deep it is.

In the video, the screws on the dresser mark the exact spot.

Why this matters for your wallet

Knowing the exact location and depth means:

  • Less concrete to break
  • Less flooring to remove and replace
  • A clear choice between going through the floor or tunneling under it
  • An estimate based on what's actually wrong, not a guess

A question to ask any plumber

If someone quotes you a large slab repair without running a camera and locating the problem first, ask them how they know where the problem is.

Frequently Asked Questions

How do plumbers find a broken pipe under a slab?

For drain lines, they run a sewer camera to the problem and use a locator to find the camera's transmitter from above. That gives the exact spot and depth.

Do you have to break up the floor to fix a drain under a slab?

Not always. Some repairs can be done by tunneling under the slab from outside. Locating the problem first shows which option makes sense.

Related