Slab Leak Detection: Find Hidden Water Leaks Under Your Foundation

Written by Steven Shipler, Texas Licensed Master Plumber (License #45825), Responsible Master Plumber (RMP), MBA, and host of The 4 Guys Education on YouTube.

A slab leak is a water line leak underneath or inside the concrete slab your home sits on. You cannot see it, but it can run up your water bill, undermine your foundation, and cause mold and damage long before you ever spot a puddle. Slab leak detection finds exactly where that leak is, without jackhammering your whole floor to go looking for it. With Lone Star Leak Locators, you will receive a certified Master Plumber Report that documents the leak and what it means.

What Is a Slab Leak?

Most homes in Texas are built on a concrete slab foundation, with water lines running through or beneath it. A slab leak happens when one of those pressurized water lines springs a leak under the concrete. Hot water lines are especially prone to it. Because the leak is hidden under the slab, the water has nowhere to go but into the soil and concrete, which is where the real damage starts.

Signs You May Have a Slab Leak

Slab leaks are sneaky, but they leave clues. Watch for:

• A water bill that jumps with no change in usage
• The sound of running water when everything is turned off
• A warm or hot spot on the floor (often a hot water line leak)
• Low water pressure
• Cracks in the floor or walls
• Damp carpet, warped flooring, or a mildew smell
• The water meter moving while no water is being used

How Slab Leak Detection Works

The whole point of professional slab leak detection is to find the leak precisely so the repair can be small and targeted, instead of guessing and opening up the whole slab. We use non-invasive equipment to listen for and pinpoint the leak through the concrete, then mark the exact spot. The process usually includes isolating the system, pressure testing to confirm a leak exists, acoustic listening to hear it, and thermal imaging to confirm a hot-water leak.

You Will Receive a Certified Master Plumber Report

This is what sets us apart. A lot of leak calls end with a technician pointing at the floor and a sales pitch. With Lone Star Leak Locators, you will receive a certified Master Plumber Report, prepared and stood behind by a licensed Texas Master Plumber, Texas License #45825, Registered Master Plumber. That license represents years of training, testing, and legal accountability for the work.

Your certified Master Plumber Report includes:

• The confirmed location of the leak, marked so any repair is precise.
• Documentation of the findings in plain language.
• Whether it is a hot or cold water line and what that means.
• Your repair options, from a targeted spot repair to a reroute or repipe.
• A Master Plumber’s professional opinion you can act on with confidence.

Pipe & Leak Inspection Videos

These videos show why hidden pipe problems are worth finding before they cause real damage. Camera and detection evidence takes the guesswork out of what is happening behind the walls and under the slab.

What Causes Slab Leaks?

Slab leaks rarely happen for one reason. Common causes include:

• Abrasion: pipes rubbing against concrete, gravel, or rebar as water flows.
• Corrosion: older copper or galvanized lines breaking down over time.
• High water pressure: stressing the lines until they fail.
• Foundation and soil movement: expansive Texas clay shifting the slab and the pipes in it.
• Poor original installation: kinked or improperly supported lines.

What the Findings Mean

Detection is only useful if it leads to the right next step. Here is how common findings translate:

Repair Options After Detection

Once the leak is pinpointed, you generally have three paths, and the report helps you choose: a targeted spot repair that opens only the small area over the leak, a reroute that bypasses the bad section with a new line, or a repipe when the lines are old and failing in more than one place. The right answer depends on the pipe’s age, the location, and how many issues we find.

What Our Customers Say

Service Area: Dallas-Fort Worth

We provide slab leak detection across the Dallas-Fort Worth metro.

City References: Plano, Dallas, and Frisco

Slab leaks show up across North Texas, and the cause is usually the same with a different address:

1. Plano, TX: expansive clay soil and slab foundations make hidden water-line leaks a common, costly surprise.
2. Dallas, TX: older homes with aging copper and galvanized lines are prone to corrosion-driven slab leaks.
3. Frisco, TX: newer slab homes can still develop leaks from soil movement, pressure, and abrasion.

Tools and Equipment Used

Precise slab leak detection depends on the right equipment and the experience to read it:

1. Acoustic leak detection equipment: ground microphones and listening discs that pinpoint the sound of water escaping under the slab.
2. Electronic leak detection: electro-acoustic amplification that isolates and locates the leak signal through concrete.
3. Thermal imaging camera: detects the temperature difference from a hot water line leaking under the floor.

Helpful Internal Links

• Slab Leak Detection Plano TX
• Slab Leak Detection Dallas TX
• Slab Leak Detection Frisco TX
• Water Leak Detection Plano TX
• Pool Leak Detection Plano TX
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