Leak & Slab Detection

Leak detection is the use of specialized instruments — acoustic sensors, thermal imaging, and pressure testing — to locate hidden water leaks without destructive searching. A slab leak is the most consequential kind: a leak in a water or drain line buried beneath or within a concrete slab foundation, where escaping water erodes soil, damages flooring, and can threaten the foundation itself if left alone.

Think you have a hidden leak? Do this now. Turn off every fixture and water-using appliance, then watch your water meter — if it is still moving, water is escaping somewhere. Check for the classic signs below: warm spots on the floor, the sound of running water with nothing on, a bill that jumped for no reason. Then call (833) 834-1087. We confirm the leak with instruments, pinpoint its location before any concrete or drywall is opened, and quote the repair upfront — detection is far less costly than the foundation damage an unchecked leak invites.

How leak detection works

Finding a leak you cannot see is a measurement problem, and each instrument measures something different. Used together, they triangulate — the same principle as finding a sound in a dark room by listening from several positions.

Acoustic leak listening

Pressurized water escaping through a crack or pinhole makes a distinct sound — a hiss or whoosh as water jets into the surrounding soil or slab. An acoustic ground microphone, essentially a highly sensitive listening disc coupled to the floor or ground, picks up that vibration while filtering ambient noise. The technician listens at multiple points along the suspected line: the sound grows louder approaching the leak and fades past it, so a series of readings triangulates the loudest point — and the loudest point is the leak. Acoustic detection works best on pressurized supply leaks, in quiet conditions, and through hard surfaces that transmit vibration well. A hot-water slab leak often announces itself acoustically before any other symptom appears.

Thermal imaging

An infrared camera reads surface temperature differences invisible to the eye. A hot-water line leaking under a slab warms the concrete above it in a characteristic plume pattern; a cold-water leak can show as a cool anomaly against a warm slab. Thermal imaging surveys large areas fast — an entire floor in minutes — making it the ideal first sweep before acoustic equipment narrows the search. Its limits are honest ones: thick flooring, insulation, and radiant barriers mute the signal, and it reads temperature, not water, so every thermal hit gets confirmed by another method.

Pressure testing

When the question is whether a leak exists at all — and which part of the system holds it — pressure testing answers definitively. Sections of the supply system are isolated with valves, a gauge is attached, and the line is pressurized and watched. A holding gauge means that zone is sound; a dropping gauge means water is escaping somewhere inside it. By testing zones separately — hot versus cold, one bathroom branch versus another — the technician narrows the leak to a specific run before any listening equipment comes out. It is methodical, unglamorous, and conclusive.

Moisture meters and tracer gas

Pin and pinless moisture meters map dampness in drywall, wood, and flooring, tracing a hidden leak’s migration path back toward its source. For leaks that defeat every other method — tiny, intermittent, or under complex construction — tracer gas (a safe hydrogen-nitrogen mix introduced into the drained line) escapes at the leak point and is sniffed out at the surface with a sensitive detector. Between these four approaches, a leak has nowhere left to hide.

Drain-side leaks and sewer cameras

Not every slab leak is a supply leak. Drain lines under the slab can crack, separate at joints, or corrode through — leaking wastewater into the soil below. These do not show on pressure tests (drains are not pressurized) and sound different acoustically. A sewer camera pushed through the drain line shows breaks, separations, and root intrusions directly, with a locator sonde marking the exact position from above. Supply-side and drain-side leaks demand different repairs, so distinguishing them is the first job.

Slab leak repair options

Pinpointing the leak is half the job; choosing the repair is the other half. Three approaches exist, and the right one depends on the leak’s location, the pipe’s overall condition, and what sits above it.

Direct access: open and repair

The concrete is opened at the pinpointed location — a small, surgical cut, not a trench — the failed section is repaired or replaced, and the slab is repoured. This is the most direct fix for a single, confirmed leak in otherwise sound pipe, and it disturbs the least flooring when the leak sits under tile or in a utility area. Its weakness is statistical: one slab leak in aging pipe often predicts the next, and opening the slab twice costs more than rerouting once.

Reroute: abandon and go overhead

The leaking under-slab line is capped and abandoned in place, and a new line is run overhead — through walls and attic spaces — to the same fixtures. No concrete is broken, flooring stays intact, and the new line is accessible for any future work. Rerouting is the preferred answer when the pipe is old enough that more leaks are likely, or when the leak sits under expensive finished flooring. The trade-off is a longer pipe run with more fittings, installed to be protected from freezing and physical damage.

Tunneling: dig under from outside

A tunnel is dug beneath the slab from outside the foundation to reach the leak from below. Flooring and interior finishes are never touched. Tunneling suits leaks under areas where breaking the slab from above is impractical, and it allows full replacement of a damaged under-slab section. It is the most labor-intensive option and needs adequate soil conditions and clearance — but for the right situation, it preserves the home’s interior completely.

Signs you need leak detection

• A water bill that jumps with no change in usage.
• Warm spots on a concrete floor — a hot-water line leaking below.
• The sound of running water when every fixture is off.
• Damp carpet, warping wood, or mildew where no spill occurred.
• Cracks appearing in floors, walls, or the slab itself.
• Low water pressure that affects the whole house.
• A water meter that moves with all fixtures off.
• Musty odors from floors or lower walls.
• Foundation soil that stays wet or shifts near plumbing entries.
• Mold or mildew blooming on baseboards.

What leak detection service includes

• Acoustic leak listening with professional ground microphones.
• Thermal imaging surveys of floors and walls.
• Pressure testing of supply lines, zoned to isolate the leak.
• Moisture mapping to trace a leak’s migration path.
• Slab leak pinpointing before any concrete is cut.
• Sewer camera inspection for drain-side leaks.
• Marked leak location with readings and photos as evidence.
• Repair plan — spot repair, reroute, or tunneling — with upfront pricing.
• Coordination with repiping when the pipe’s condition says one leak means more coming.

What a leak detection visit looks like

Step 1 — Rule out the easy things. Running toilets, dripping faucets, irrigation leaks, and water softeners stuck in regeneration all mimic hidden leaks on a water bill. The technician eliminates these first, because the detection you avoid paying for is the one you do not need.

Step 2 — Confirm and isolate. The meter test and zoned pressure testing confirm a leak exists and narrow it to a section of the system — hot or cold, which branch, supply or drain side.

Step 3 — Pinpoint. Thermal imaging sweeps the area, acoustic listening triangulates the exact point, and moisture mapping corroborates. Multiple methods agreeing on one spot is the standard before anyone recommends opening concrete.

Step 4 — Evidence and options. You get readings, thermal images, and a marked location — plus the repair options that fit: spot repair, reroute, or tunneling, each with upfront pricing and an honest assessment of the pipe’s overall condition. A single leak in young pipe gets a spot repair; a leak in pipe that is failing everywhere gets a different conversation.

Preventing slab leaks and hidden leaks

Water pressure is the master variable: excessive pressure stresses every joint and accelerates pinhole corrosion, so a pressure-reducing valve set correctly protects the entire system. Water quality matters too — hard, mineral-heavy water scales and corrodes from the inside, which is why water treatment is leak prevention as much as comfort. Know your main shutoff and check it yearly. Watch the water bill for unexplained movement — it is the most cost-effective leak detector ever made. And in expansive-soil regions, keeping foundation moisture reasonably consistent reduces the soil movement that stresses buried lines. None of this prevents every leak, but it shifts the odds decisively.

What affects the cost of leak detection and repair

Detection itself is the smaller, predictable part — the instruments and the technician’s time. Repair cost hinges on what the leak turns out to be. A supply-line leak versus a drain-line leak means different repairs. Location under the slab matters: depth, what flooring sits above, and how far the leak is from an access point. The repair method chosen — spot repair, reroute, or tunneling — carries different labor and restoration profiles, and honest guidance weighs the pipe’s overall condition, not just today’s leak. Flooring restoration varies widely between tile, wood, and carpet. What stays constant: you approve a flat-rate price for both detection findings and the repair before any concrete is touched.

Related plumbing services

Leak detection is often the beginning of a larger decision. When instruments reveal a system riddled with pinholes or corrosion rather than one bad joint, whole-home repiping ends the cycle permanently. When water is actively damaging the home, emergency plumbing contains it first and detects second. When the camera shows the leak is in the drain lateral rather than the supply, sewer line services handle the repair, trenchless where the line qualifies. Detection connects them all — it is how you spend money on the right fix instead of the obvious one.

Leak and slab detection FAQs

How do you find a leak under concrete without tearing up my floor?

With instruments, not jackhammers. Acoustic sensors listen for the sound of escaping water and triangulate the loudest point; thermal cameras map temperature anomalies from hot-water leaks; pressure tests confirm which zone holds the leak. We open concrete only at the pinpointed spot, after multiple methods agree.

Is a slab leak an emergency?

It can wait days, not months. An active slab leak erodes soil under the foundation, feeds mold, and damages flooring — the damage compounds while you wait. Detection this week is far less costly than foundation work next year.

My water bill doubled but I see no leak. Where is the water going?

Into the ground or inside your structure. A supply leak under a slab or behind walls can run for weeks invisibly — the meter test (all fixtures off, watch the meter) confirms it in minutes, and our instruments find it from there.

What does a slab leak sound like?

Often like faint running water or hissing inside walls or under floors when nothing is on. Many homeowners hear it for weeks before connecting it to plumbing. If you hear water that should not be running, trust your ears and get it checked.

Can you detect a leak in a drain line, not just a water line?

Yes — with a sewer camera rather than acoustic gear. Drain lines are not pressurized, so we inspect them visually from the inside, locating breaks and separations with the camera’s locator. Supply and drain leaks need different repairs, so telling them apart is the first job.

Should I repair the slab leak or reroute the line?

One confirmed leak in otherwise young, sound pipe: spot repair. A leak in aging pipe with corrosion elsewhere, or a leak under expensive flooring: reroute. We show you the pipe’s condition with camera and test evidence so the choice is informed, not guessed.

Will my floors be destroyed during slab leak repair?

No — that is the entire point of pinpoint detection. Direct-access repair opens a small surgical section at the marked spot; rerouting breaks no concrete at all; tunneling works from outside. Wholesale floor destruction belongs to the era before acoustic equipment.

Does homeowners insurance cover slab leaks?

Many policies cover the resulting water damage and sometimes the access to reach the leak, while the pipe repair itself is often excluded — but policies vary enormously. Our documentation (readings, photos, marked locations) gives your adjuster exactly what they need. Check your policy’s plumbing and foundation provisions.

How accurate is acoustic leak detection?

Very, when conditions cooperate — quiet environment, hard surfaces, a pressurized leak. That is why professionals corroborate: thermal imaging plus acoustic plus pressure testing, all pointing at the same spot. A single-method guess is not a detection; three methods agreeing is.

What causes slab leaks in the first place?

The usual causes: pinhole corrosion in aging copper, abrasion where pipe rubs against concrete or rebar, excessive water pressure stressing joints, and soil movement shifting buried lines. Hard water accelerates the corrosion side; pressure regulation and treatment address the preventable causes.

A hidden leak will not fix itself — but it will get more expensive. Call (833) 834-1087 for instrument-verified leak detection with the location marked and the repair quoted upfront. We serve our full service areas across Texas, including slab leak detection in Katy, slab leak detection in Houston, and slab leak detection in Fort Worth.