Slab Leak Detection in San Diego
A slab leak is a pressurized water line failing inside the concrete under your house. Left alone it wastes water, warps flooring, and undermines the foundation. We find the exact leak point without demo and give you clear repair options in writing.
What this actually is
A slab leak is a pinhole or split in a pressurized copper line running through the concrete slab under your house. Because the pipe is under 50 to 80 psi, even a hairline crack pushes gallons per day into the sub-slab and eventually up through the flooring. The house rarely tells you exactly where it is. Our job is to prove it before anyone picks up a jackhammer.
We work in a set order: isolate the line, confirm loss with a pressure decay test, then walk the slab with an acoustic amplifier and thermal camera to pinpoint. When we mark the floor, we mark within about a foot of the actual break. That means one clean access hole, not four exploratory ones.
Slab Leak Detection
- Electronic acoustic pinpointing
Ground microphones and a correlator listen for the pressurized water escaping the pipe under the slab, then triangulate the exact break location.
- Thermal imaging on hot lines
Hot-water slab leaks warm the floor above them. A FLIR thermal camera confirms the acoustic pin and rules out false positives from HVAC runs.
- Pressure isolation and decay testing
We valve off hot and cold separately, cap fixtures, and measure the pressure drop to confirm which line is leaking before we ever go looking.
- Written diagnosis with repair options
You get a marked floor plan, photos, and both repair options priced: spot repair versus reroute overhead in PEX-A. No pressure, no guess-cutting.
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Our process, step by step
- 1Confirm the leak exists
Meter test with the house shut off. If the meter is turning, we have a leak on the pressurized side and it is time to isolate.
- 2Isolate hot vs cold
We valve down the water heater and re-test to determine whether it's a hot or cold line. That single step cuts search area in half.
- 3Pressurize and listen
Line is charged with air or water while we walk the slab with acoustic listening discs and a correlator to find the loudest signature.
- 4Thermal confirm and mark
Thermal camera confirms hot-line pins. We spray-mark the floor within a 12-inch radius of the actual break.
- 5Present repair options in writing
Spot repair through the slab, or overhead PEX-A reroute abandoning the failed line. Both prices, both trade-offs, your call.
Slab leaks are concentrated in the mid-century tract belt: Clairemont, Bay Park, Serra Mesa, Allied Gardens, Del Cerro, and Linda Vista. Those homes were built between 1955 and 1970 with soft copper cast directly into post-tension slabs. Six decades of San Diego's 15 to 20 grain-per-gallon water, plus normal thermal cycling on the hot line, pinholes the copper from the inside. Coastal humidity in Point Loma and Ocean Beach adds outside corrosion on top. Newer stucco tracts (post-2000) in Carmel Valley, Del Sur, and 4S Ranch almost never slab-leak because they were built with PEX above the slab. If your home is pre-1975 and on a slab, treat a warm floor as guilty until proven innocent.
What homeowners actually notice
If any of these match what you're seeing at home, it's worth a call before it gets worse.
- A warm or hot spot on the tile, wood, or carpet that shouldn't be warm
- Water bill jumped 30% or more with no change in usage
- The sound of running water when everything is turned off
- Cracks appearing in tile, grout, or drywall along an interior wall
- Mildew smell in a closet or under a cabinet on a slab
- Water heater running noticeably more often than it used to
What this typically costs
Slab leak detection in San Diego is typically $350 to $550, depending on square footage and how much furniture has to be moved. That fee includes the meter test, isolation, acoustic and thermal work, marking, and a written diagnosis you keep. If we then perform the repair or reroute, we credit the detection fee against the repair on the same visit.
Common questions
How accurate is slab leak detection?+
On a residential copper line we mark within about a 12-inch radius of the actual break. That's tight enough to open one 18x18 access and get straight to the pipe.
Should I repair the leak or reroute the line?+
One-time spot repair makes sense on a young house with a fresh copper system. If the home is pre-1975 or you've already had a slab leak in the last 5 years, an overhead PEX-A reroute is usually the smarter money because the rest of the line will fail next.
Will you have to break up my floor?+
Not to detect. Detection is fully non-invasive. If you choose a spot repair, we cut a single access hole roughly 18 inches square and patch the concrete when we're done.
How long can I ignore a slab leak?+
Days, not months. A pressurized leak keeps running 24/7 and can undermine soil under the footing. Once you see mold or foundation cracking, the repair bill doubles.
Does homeowners insurance cover slab leaks?+
Most San Diego policies cover the water damage and the access to repair, but not the pipe repair itself. We give you an itemized invoice that separates the two so your adjuster can process it cleanly.
Can you detect a leak under tile without damaging the tile?+
Yes. Acoustic and thermal detection are surface-only. The tile is only at risk if you choose a spot repair over a reroute, and even then we cut the smallest possible access.
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Got a leak? Give Lefty a call.
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