Locate the leak and choose the least disruptive repair.
What Is a Slab Leak?
A slab leak is a leak in a water line running in or beneath a concrete slab foundation. North Texas clay soil expands when wet and shrinks during drought, and that movement stresses pipes cast in or under the slab. Older copper lines can also wear from abrasion and the minerals in moderately hard water. Homes built from the 1960s through the 1990s with copper under the slab are frequently affected.
Signs of a Slab Leak
Warm Floors
A hot-water line leaking under tile or wood creates warm or hot spots.
High Water Bill
Water running continuously under the house. If the meter moves with everything off, see our high water bill guide.
Running Water Sound
Hearing water when no fixtures are in use, especially at night.
Foundation Moisture
Damp carpet, warped wood, mildew, or new cracks in floors or walls.
Low Water Pressure
A significant leak diverts water before it reaches fixtures. See low water pressure.
How Slab Leaks Are Detected
A leak detection technician isolates hot and cold lines, pressure-tests them, then uses acoustic and thermal equipment to pinpoint the spot. Accurate location keeps the repair opening small. See leak detection.
Slab Leak Repair Options
Direct Repair
Break the slab at the leak (or tunnel under from outside), repair the pipe, and patch the concrete. Good for a single leak in otherwise sound pipe.
Rerouting
Abandon the leaking line and run new pipe through walls or the attic. Avoids breaking concrete and is often preferred when a line has leaked before.
Repiping
Replace the supply plumbing when multiple leaks show the system is failing. See repiping.
How Much Does Slab Leak Repair Cost?
Cost depends on detection, access, method, and floor restoration. See our slab leak repair cost guide for published ranges with linked sources, plus the factors that change the price. Figures there are third-party ranges, not quotes. Many homeowners policies cover access and resulting water damage but not the pipe itself; coverage varies.
Can a Slab Leak Damage Your Foundation?
Prolonged leaks can saturate the soil under a slab, and in Dallas’s expansive clay that can contribute to movement. Fixing the leak promptly is the first step. If you see significant cracking, ask whether a foundation evaluation is warranted after the plumbing repair.
FAQs
Is a slab leak an emergency?
A significant leak should be addressed quickly to limit damage. Close the main valve if water is visibly escaping.
Is rerouting better than a direct repair?
Rerouting avoids concrete work and replaces the problem line. A direct repair can make sense for a first leak in sound pipe. Ask for both options.
Will my foundation be damaged?
Prolonged leaks can affect the soil under a slab. Fixing the leak promptly is the first step.
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