Slab Leak Detection ProsHome › Slab Leak Detection
Slab leak detectionSlab Leak Detection
Slab leak detection finds a leaking pipe under a concrete foundation without breaking the floor to search for it. A licensed plumber confirms the leak with a meter and pressure test, isolates the line, then pinpoints it with acoustic, thermal and tracer-gas tools.
- Acoustic listening
- Thermal imaging
- Tracer gas
- Pressure & hydrostatic tests
- Camera inspection
Signs of a slab leak
- Water bill jumped with no change in use
- Meter keeps moving with everything off
- Warm spot on tile, wood or carpet
- Running-water sound when nothing is on
- Water heater runs constantly
- Damp carpet, cupped wood, musty smell
- Sewer smell or slow drains
- New cracks or sticking doors
Is a warm spot on my floor always a slab leak?
Not always. Radiant heating, sun through a window or a duct under the floor can warm a spot too. A warm spot that stays warm at night, with a water heater that keeps running, points strongly to a hot-water slab leak.
What causes slab leaks in Texas
Most Texas homes are built on slabs, and much of the state sits on clay that swells and shrinks. Pipe age and material do the rest.
| Cause | What happens |
|---|---|
| Expansive clay | Blackland Prairie and Houston Black Clay swell and shrink, bending and cracking pipes. |
| Cast-iron drains | Homes built before about 1980 often have cast-iron drains that rust and crack under the slab. |
| Polybutylene | Gray PB supply pipe used from about 1978 to 1995 can fail at fittings. |
| Abrasion | Copper rubs against concrete or gravel as hot water makes it expand and contract. |
| Foundation repair | Leveling a slab can stress or break the pipes in it. |
| Hard freezes | Lines near slab edges can freeze and split, as many did in Winter Storm Uri. |
| Water chemistry | Very hard or aggressive water can scale or pit metal pipe over time. |
Is it my foundation or a plumbing leak?
It can be either, or both. A leak can soften the soil and let part of the slab settle, and clay movement can crack a pipe. If you see new cracks and your water bill is up, test the plumbing before paying for foundation work.
What our slab leak detection covers
We do one thing: find leaks under concrete slabs. Every visit is done by an independent, licensed Texas plumber who specializes in leak detection, so you pay to find the leak, not to break concrete searching for it.
Water Line Leaks
Find leaks in the pressurized supply lines buried in or under your slab.
Hot-Water Line Leaks
Thermal imaging traces warm spots and leaking hot-water runs.
Drain Line Leaks
Hydrostatic and isolation tests find drain leaks that never show on your meter.
Pressure Testing
Confirm a leak exists and measure how fast the line loses pressure.
Line Isolation & Tracing
Separate hot, cold and branch lines and map where they really run.
Acoustic Pinpointing
Ground microphones hear escaping water through the concrete.
Tracer Gas Detection
For very quiet leaks and plastic pipe, gas rises at the leak point.
Written Leak Report
Exact location, readings and photos for your insurer or water utility.
How we find a slab leak without tearing up your floor
The same nine steps on every job, so you know what’s happening and why. Read the full process →
Listen and look first
The plumber hears what you've noticed and walks the home to look for clues.
Rule out the easy causes
Toilets, faucets, irrigation, the water heater and the AC drain are checked so you don't pay to search for the wrong leak.
Confirm the leak with the meter and a pressure test
A meter test and a pressure test prove water is escaping from the plumbing.
Isolate the leaking line
Hot, cold and branch lines are separated so the search focuses on the one that's leaking.
Test the drains, if needed
Drain leaks don't show on the meter, so they get their own hydrostatic test and camera check.
Trace the pipe's route
An electronic locator maps where the leaking line actually runs under the floor.
Pinpoint the exact spot
Acoustic listening, thermal imaging and tracer gas find where the water is escaping, and two methods must agree.
Scan the slab and mark the leak
The slab is checked for steel tendons and rebar, and the leak is marked on the floor.
Get your written report
You receive the leak's location, the line, the readings and photos in writing.
What does tracer gas detection do?
The line is drained and filled with a safe mix of about 5% hydrogen and 95% nitrogen. The gas escapes at the leak and rises through the slab, where a sensitive detector finds it. It works well on quiet leaks and plastic pipe.
Supply leaks
Supply lines are pressurized, so they leak all the time and show up on your meter and bill. They’re found with pressure tests, acoustic listening, thermal imaging and tracer gas.
Drain leaks
Drain and sewer lines leak only when water runs down them, so your meter won’t show it. They’re tested with a hydrostatic test, then a camera inspection and isolation test to find the broken section.
Why won't my water meter show a drain leak?
Your meter only measures water coming into the house. A broken drain leaks water that's already been used, so it never shows on the meter. That's why drains are checked with a hydrostatic test and a camera.
Water coming up through the floor?
Shut off the main water valve and call now. We’ll connect you with a licensed slab leak specialist.
Slab leak specialist vs. general plumbing contractor
Many general plumbers do excellent work. The difference is focus and equipment when the leak is hidden under concrete.
| What matters | Slab leak detection specialist (our network) | Typical general plumbing contractor |
|---|---|---|
| Main focus | Only finding hidden leaks under slabs | Installs, repairs and remodels across all plumbing |
| Detection tools | Acoustic ground mics, thermal imaging, tracer gas, line tracing | Varies; often a pressure test and visual inspection |
| Locating the leak | Pinpointed before any concrete is opened | May open the floor in more than one place to search |
| Drain leaks under slab | Hydrostatic, isolation test and camera find the broken section | May recommend replacing the whole drain system |
| After the leak is found | Exact spot marked and documented; you choose who fixes it | Often moves straight into its own repair or repipe |
| Paperwork | Written report with photos for insurance and water credits | Usually an invoice only |
| Typical cost to locate | $150–$600 | Varies; exploratory openings add cost |
Tip: whoever you call, ask which detection methods they use and whether they’ll pinpoint the leak before opening the slab.
What slab leak detection usually costs
Published national and Texas ranges. You get the price before the visit.
Slab Leak Detection
- Meter & pressure testing
- Hot/cold line isolation
- Acoustic & thermal pinpointing
- Leak marked on the floor
- Written report with photos
What raises the price
- Larger homes with more lines
- More than one leak
- Very quiet leaks needing tracer gas
- Drain testing (a hydrostatic test is typically about $250)
- After-hours visits
What it doesn’t include
- Breaking or patching concrete
- Pipe repair or rerouting
- Foundation work
- Mold cleanup
We only do detection. You get the exact location and choose who does any repair.
Sources: This Old House, Angi/HomeAdvisor via Bob Vila.
Can you tell whether the hot or cold line is leaking?
Yes. Closing the cold-water inlet at the water heater isolates the hot side. If the meter stops, the leak is on a hot-water line; if it keeps moving, it's on the cold side. Each line is then tested on its own.
Insurance and slab leaks in Texas
Coverage depends on your policy and the cause. The Texas Department of Insurance has long said the standard HO-B policy covers damage to the dwelling, including the foundation, from an accidental discharge of water from a plumbing system. Many policies still exclude wear and tear, the pipe itself, and mold.
What helps your claim: shut off the water, protect your belongings, and get the leak documented by a licensed plumber before the adjuster visits.
Ask for a leak credit
Many Texas cities and MUDs credit part of the water lost to a hidden leak once it’s repaired. Most want a paid plumber’s invoice and a request within a set number of days, and allow one credit a year.
Keep your invoice, and call your utility soon after the repair to ask about its rules and deadline.
Questions about slab leaks?
Still not sure if you have a slab leak? Call and describe what you’re seeing. A licensed plumber will tell you whether it’s worth a visit.
Call (000) 000-0000How do I know if I have a slab leak?
The most reliable home check is the meter test: turn everything off and watch the meter for one to two hours. Other common signs are a sudden jump in your water bill, a warm spot on the floor, the sound of running water and a water heater that never stops running.
Can a slab leak be found without breaking the floor?
Yes. Detection is non-invasive. A plumber pinpoints the leak with pressure tests, acoustic listening, thermal imaging and tracer gas, then marks the exact spot, so nobody has to break concrete to search for it.
Is a slab leak an emergency?
A large leak, water coming up through the floor or a sewer smell needs help the same day. Even a slow leak should be checked within days, because water under a slab can wash out soil, move the foundation and grow mold.
Does homeowners insurance cover a slab leak in Texas?
Often in part. Many Texas policies cover damage from an accidental discharge of water, including tear-out to reach the pipe, but exclude wear and tear and the pipe itself. Check your policy and call your insurer early.
What is a hydrostatic test?
A hydrostatic test checks drain and sewer lines under the slab. A test ball seals the main line, the system is filled with water to slab level, and the level is watched. If it drops, a drain is leaking.
What do I get after slab leak detection?
The leak's exact location marked on the floor, which line is leaking (hot, cold or drain), the test readings and photos, and a written summary you can give your insurer or your water utility.