Finding and repairing slab leaks in San Jose
A slab leak runs under the concrete where you cannot see it, so the work is in finding it precisely before anything is cut.
- 24/7 answered
- Phelan Ave San Jose office
- Tank, tankless, heat pump
Perfect Tankless Plumbing, San Jose, CA
A slab leak in San Jose is a supply or drain pipe leaking under a concrete floor; we confirm it with meter and pressure tests, pinpoint it with acoustic and thermal equipment, then either repair it through a small opening in the slab or reroute the line overhead so the slab is left alone.
Updated September 2026
Emergency & Leaks
How slab leaks are found
Slab leaks show up as symptoms rather than water: a meter that moves with everything off, a warm patch on the floor from a hot line, the sound of running water, damp carpet near a wall, or a bill that climbs for no reason.
We isolate hot and cold with pressure tests, then listen through the floor with acoustic equipment and look for heat with a thermal camera. The goal is to open the slab once, in the right place, or to decide that a reroute is the better repair.
Warning signs
Signs of a slab leak
- Warm floor patchA hot water line leaking under the slab.
- Meter movingWater use with everything turned off.
- Running water soundWhen no fixture is open.
- Damp flooringCarpet or baseboards wet near a wall.
- Higher water billUsage up with no change in habits.
- Weak hot waterPressure lost to the leak.
Spot repair through the slab
When the leak is isolated to one spot and the pipe around it is sound, we cut a small, square opening in the slab at the located point, excavate to the pipe, replace the failed section, pressure test, and patch the concrete. Flooring over the spot has to be lifted and later replaced, which we plan with you before cutting. Spot repair makes sense on newer pipe with a single defect, and much less sense on old copper that is thinning everywhere under the floor.
Reroute overhead
A reroute abandons the failed line under the slab and runs a new one through the attic and down inside the walls to the fixtures it served. It avoids breaking the floor and replaces a whole run of aging pipe instead of one spot. It is often the better choice when the pipe has already leaked once, when the leak sits under tile or cabinets, or when the house has several lines of the same age. Small wall openings are needed where the new pipe drops to each fixture.
Eichler radiant slab considerations
Eichler homes carry radiant heating loops inside the slab alongside, and sometimes near, the domestic water lines. Before any cutting we identify which system is leaking, because a radiant loop leak is a heating problem with different repair options. If a domestic line is at fault, reroute is usually preferred in an Eichler, since cutting the slab risks the radiant tubing and the finished floors many owners have restored carefully. We map the radiant layout from the heat signature before anything is drilled.
How the job runs
How a slab leak job runs
- 1
Confirm the leak
Meter test with fixtures off.
- 2
Isolate hot or cold
Pressure test each side.
- 3
Pinpoint
Acoustic and thermal locating.
- 4
Choose the repair
Spot repair or reroute, with the trade-offs.
- 5
Repair
Cut and replace, or run the new line.
- 6
Test and restore
Pressure test, patch and document.
Local context
Slab leaks in San Jose's Eichler tracts
San Jose's Eichlers are slab-built with radiant heat cast into the concrete, spread across tracts that include Fairglen, the early homes in Rose Glen near San Jose City College, and Fairhaven near Campbell. The Fairglen Additions are listed on the National Register of Historic Places, and many owners there have restored original floors. That is why we map the radiant loops thermally and lean toward rerouting domestic lines rather than opening the slab in those houses.
Options
Spot repair or reroute
| Spot repair | Reroute | |
|---|---|---|
| Floor opening | Yes, at the leak | No |
| Wall openings | No | Small, at fixtures |
| Pipe replaced | A short section | The whole run |
| Best for | Newer pipe, single defect | Aging pipe or repeat leaks |
| Flooring impact | Lifted and replaced at the spot | Untouched |
| Future leaks on that line | Possible elsewhere | Line abandoned |
Cost factors
What changes the cost of a slab leak repair
We do not publish a local slab leak price; the method and what sits on top of the slab set the scope.
- Locating time. a clear signal is faster than a faint one
- Repair method. spot repair or reroute
- Flooring. tile, hardwood or carpet over the leak
- Pipe age. older lines favor rerouting
- Radiant heat. extra care in Eichler slabs
- Wall and ceiling access. needed for a reroute
FAQ
Slab Leak Repair questions from San Jose homeowners
Pressure tests narrow it to hot or cold, then acoustic listening and thermal imaging pinpoint the spot.
Spot repair suits a single defect on sound pipe. Rerouting suits older pipe or leaks under finished floors.
A spot repair opens a small area of slab and flooring. A reroute leaves the floor alone.
Water under a slab can wash out soil over time, which is why it's worth fixing promptly.
Yes. Radiant heating loops share the slab, so we identify which system is leaking before any cutting.
Same family
Related work in emergency & leaks
Ceiling and Wall Water Damage Plumbing
Upstairs bathroom leaks, Stack and vent leaks.
How we handle ceiling and wall water damage plumbingLeak Detection
Acoustic and thermal locating, High water bill investigation.
How we handle leak detectionRadiant Slab Heating Leak Repair
Pressure loss on the boiler, Locating the loop leak.
How we handle radiant slab heating leak repairPipe Leak Repair
Under-sink joints, Crawl space lines.
Pipe Leak RepairMain Water Line Repair
Meter-to-house line, Trenchless water line.
Read about main water line repair
One number, any hour
Find the leak under your floor
Call and describe what you are seeing. We will locate it before recommending a repair.
