The situation

Illustrative example. Not a real job or customer.

A single-story 1950s house on a slab has its original copper water lines under the floor. The owners notice a warm patch on the hallway tile outside the main bathroom, and the water heater seems to run more often than usual.

  1. They turn off every fixture and check the meter; the leak indicator turns steadily.
  2. They close the water heater's cold inlet, and the indicator stops, pointing to the hot side.
  3. They call two licensed plumbers, checking each license at cslb.ca.gov, and book leak detection with one of them.

The owners arrive at the appointment already knowing the leak is on the hot-water side, which shortens the diagnosis.

How the days might go

Day 1, evening
Warm floor noticed; meter test done; water heater inlet closed overnight to stop losing hot water.
Day 2
Leak detection confirms a hot line leak under the hallway using pressure testing, thermal imaging and acoustic listening.
Day 2
Plumber explains options: open the tile for a spot repair, or reroute the hot line to the bathroom through the attic.
Day 3
Owners compare the written scopes, call their insurer and choose the reroute.
Day 4 to 5
New line run in the attic and down the wall; old line capped; system pressure-tested.
Later
Drywall openings patched; permit inspection completed if required.

Why the owners chose a reroute

Spot repair

  • Would break and replace hallway tile they could not easily match.
  • Would keep the rest of the original under-slab hot line in service.

Reroute

  • Avoided breaking the floor.
  • Took the failing line out of service entirely.
  • Required small drywall openings that were simpler to patch.

What made this go smoothly

The owners caught the leak early because they paid attention to a warm floor and did the meter test themselves. Closing the water heater inlet overnight limited water loss and confirmed the hot side.

They also asked for a written scope for each option before deciding, which let them weigh tile replacement against drywall patching instead of choosing in a hurry. In a different house, with sturdier flooring or newer pipe, a spot repair might have been the better call.

Questions this example raises for your house

  1. Do you know whether your water lines run under the slab or through the attic?
  2. Have you ever had a slab leak before, and on which line?
  3. Which flooring would be hardest to replace if the slab had to be opened?

Common questions

Is this a real La Mirada job?

No. It is an invented example to illustrate a common type of slab leak.

Would every slab leak be rerouted?

No. The right choice depends on the leak location, flooring, pipe condition and the owner's priorities.

How was the leak located without breaking the floor?

In this example, by isolating and pressure-testing the line and using thermal imaging and acoustic listening to narrow the spot.

General information for La Mirada, not a quote or professional advice. In an emergency, call 911.