A slab leak is a supply line leaking under the concrete floor. In San Diego tract houses that is a common failure, because a lot of the housing stock sits on a slab with copper buried in it.
The first bill is finding it. Electronic leak detection on a house typically runs $250-$700. That visit should tell you whether the meter is moving with the fixtures off, and it should mark a spot. A repair quoted before that mark is a guess.
A located repair with a small concrete cut typically runs $1,500-$4,500. Rerouting that one run through a wall or the attic often runs $2,000-$6,000, and it can be the better job when the floor above the leak is tile you do not want broken. A whole-house repipe is a different project, typically $4,500-$12,000 for a single-story house, and it makes sense when this is the second or third leak.
Hot-side leaks warm the floor. Cold-side leaks often only show up on the bill or as a hiss under the slab. Neither one tells you the pipe is fine because the stain is small. Water under a slab keeps moving.
Pipe Pro SD does not do the repair. We match the call to a local plumber. Ask for the detection and the repair as separate numbers, and look up the contractor at cslb.ca.gov before anyone cuts the floor.