Slab Leak Repair
Leaks in copper lines beneath concrete floors fixed by spot repair, attic or wall reroute, or a full repipe, chosen for your house and slab.
See the detailsLeak detection in Los Angeles that finds the pipe before we open a wall
Your water bill jumped, a baseboard feels soft, or you hear water running when every tap is off. We track the leak to a specific spot so the repair starts with one small opening instead of a torn-up room.
- Answered 24/7
- From 746 S Broadway
- Repairs & emergencies
The short answer
Leak detection is the process of confirming that water is escaping somewhere you cannot see, then narrowing it to an exact spot before anything is cut. We read the meter, isolate hot and cold lines, pressure test sections, and use acoustic listening and thermal imaging. You need it when the bill rises without explanation, the meter moves with everything off, or floors and walls show moisture.
Warning signs
Clues that a hidden leak is running somewhere in the house
- Meter dial turning with taps offShut every fixture and watch the small leak indicator on the meter for ten minutes. If it spins or creeps, water is leaving the system somewhere.
- Bill higher with no new habitsA steady drip inside a wall rarely shows up in one month. Compare the same billing period from last year to see the trend.
- Warm patch on the floorA spot on tile or hardwood that feels warmer than the rest often sits over a hot water line leaking under the slab.
- Paint bubbling near the baseboardMoisture wicking up drywall lifts paint and swells baseboards long before you see standing water.
- Musty smell in one closetA closed cabinet or closet that smells damp may share a wall with a supply line or shower valve that is weeping.
- Hissing at a quiet hourAt night, with the house still, a pinhole leak under pressure can make a faint hiss you can follow to one wall.
How we narrow a leak down without guesswork
The first job is to split the house into pieces. We close the valve at the water heater to separate hot from cold, then watch the meter again. If the dial stops, the leak is on the hot side. If it keeps moving, we close individual fixture stops and branch valves until the loss disappears and we know which run of pipe is responsible.
With the section isolated, we listen. An acoustic ground microphone picks up the sound water makes as it sprays out of a pinhole or split. Thermal imaging helps on hot lines and on wet drywall, which shows up cooler than the dry wall around it. A moisture meter confirms what the camera suggests before we mark anything.
Only after those readings agree do we mark the spot. That way the opening is usually the size of a hand or a single floor tile, not a trench across the kitchen.
Supply leaks, drain leaks and irrigation leaks are not the same hunt
A pressurized supply leak loses water all the time and moves the meter. A drain leak only loses water when someone runs a fixture, so the meter stays still and the evidence is a stain, an odor or a wet ceiling below a bathroom. We test drains by running one fixture at a time and watching with a camera or a moisture meter.
Irrigation lines and the pipe between the meter and the house are a third category. A broken sprinkler lateral or a split main service line can push water into a lawn or driveway joint for months. If the leak is outside, we check the yard line and, when it is old galvanized pipe, talk about replacing the service line rather than patching it again.
- Supply leaks: meter moves, constant loss, often hot side
- Drain leaks: meter still, damage appears after use
- Shower valve and pan leaks: stain below, only during showers
- Yard and service line leaks: soggy ground, sinking pavers
Why so many Los Angeles leaks hide under concrete
A large share of Valley houses from the 1940s through the 1960s were built on slabs with copper supply lines run through or under the concrete. Hot water lines in particular expand and contract every day, and where the copper rubs against concrete or gravel it thins until a pinhole opens. Expansive clay soil in parts of the Valley can also shift the slab and stress the pipe.
When the readings point under the floor, our next call is whether to repair at that spot or abandon the line and run a new one through the attic or walls. Our slab leak repair page explains that choice in detail, and the article on slab leak signs in Valley homes lists what owners usually notice first.
What you get after a leak detection visit
You get a clear answer: where the leak is, what kind of pipe it is in, how fast it is losing water, and the repair options with prices. We mark the location on the floor or wall and photograph the readings so you have them for your records and for any insurance conversation you choose to have.
If we find more than one problem, such as a weeping toilet flapper on top of a hidden line leak, we tell you both. Running toilets are one of the most common reasons for a high bill in LA, and a quick toilet repair sometimes solves the mystery without opening anything at all.
On the job
Steps in a hidden leak search
- STEP1
Meter and fixture check
We confirm the loss on the meter, then rule out toilets, faucets, the water heater relief valve and irrigation before looking inside walls.
- STEP2
Isolate the system
Closing valves in sequence tells us whether the leak is on the hot side, the cold side, a branch line or the yard service.
- STEP3
Pressure test sections
We cap and pressurize suspect runs with a gauge to watch for a drop that confirms which section is failing.
- STEP4
Listen and image
Acoustic microphones, thermal imaging and moisture meters close in on the exact spot along that run.
- STEP5
Mark and explain
We mark the location, show you the readings, and price the repair or reroute before any opening is made.
Leak hunting in LA homes, from slab tracts to hillside raised floors
Slab-on-grade tract homes across the San Fernando Valley hide copper in concrete, while older raised-foundation houses in neighborhoods closer to downtown let us crawl underneath and often see the drip directly. Hard water from Colorado River and State Water Project supplies leaves scale that roughens pipe interiors and wears valve seats. In the City of Los Angeles the meter belongs to LADWP and sits in a sidewalk box; other cities read their own meters and set their own leak adjustment rules. Hillside homes with long service lines up steep driveways add another place for water to escape.
Typical pricing
What leak detection typically costs in Los Angeles
Cost follows the size of the house, how many systems need testing, and whether the leak is under a slab, in a wall or out in the yard.
| Job | Typical LA range |
|---|---|
| Meter test and fixture check for a single-family home | $150 to $350 |
| Electronic leak detection on a slab or wall line | $350 to $750 |
| Yard service line or irrigation leak locate | $300 to $650 |
| Multi-unit building leak search across several units | $600 to $1,500 |
These are typical ranges, not a quote, and the price moves with the number of units, access to the meter, and how many separate systems we have to test. See every job in our LA price guide.
Questions we hear
Leak Detection questions from LA customers
Can leak detection find a leak without cutting into my walls in Los Angeles?
Locating the leak does not require cutting. We use the meter, valve isolation, pressure testing, acoustic listening and thermal imaging to pinpoint it from outside the wall or floor. The repair itself usually needs one small opening at the marked spot, and on slab leaks we sometimes avoid opening the floor entirely by rerouting the line overhead.
How accurate is electronic leak detection on a concrete slab?
On a pressurized line under a slab, acoustic and thermal readings usually narrow the leak to within about a foot, which is close enough to open one tile. Accuracy drops on very deep lines, thick carpet pads or noisy houses, so we confirm with more than one method before we mark the floor.
Will LADWP adjust my bill after a hidden leak is repaired?
LADWP and many other city water departments have a process for adjusting a bill after a leak is fixed, and policies change. Keep the repair invoice and the photos we take of the leak and readings, since those are the documents a utility usually asks for. We do not handle the application, but we give you clear paperwork for it.
Why does my water meter move only when the sprinklers are on?
That points to the irrigation system rather than the house plumbing. A cracked lateral, a broken head or a leaking valve in the control box can lose a lot of water during each cycle. Run one zone at a time and look for soggy ground or a geyser. We can trace the line if the leak is buried.
Coverage
Where we handle leak detection most
These are the communities that call us for this most often, with their main ZIP codes. The same 24/7 line covers every one of our 68 service areas.
- Los Angeles 90014
- Long Beach 90802
- Santa Clarita 91355
- Glendale 91205
- Pasadena 91101
- Torrance 90503
- Downey 90241
- Burbank 91502
- Reseda 91335
- Sylmar 91342
- Pacoima 91331
- Panorama City 91402
- North Hills 91343
- San Pedro 90731
- Granada Hills 91344
- Inglewood 90301
- El Monte 91731
- West Covina 91790
- Anaheim 92805
- Santa Ana 92701
- Whittier 90601
Often booked together
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See the detailsNeed leak detection today?
Call the line any hour. A plumber answers, asks what you are seeing and tells you what happens next.