How do I know if I have a slab leak?

Common signs include warm spots on the floor, the sound of running water when all taps are off, an unexplained spike in your water bill, buckling flooring, and new cracks in walls or baseboards.

What happens if a slab leak is ignored?

It only gets worse. Ongoing water erosion can undermine the concrete slab, destroy flooring from below, encourage mold growth, and lead to far more expensive structural repairs.

Do plumbers have to break up the whole floor to find a slab leak?

No. Modern electronic leak detection uses acoustic and thermal equipment to pinpoint the leak's location through the slab, so repairs open the smallest possible area.

Slab Leak Signs: How to Tell If You Have a Leak Under Your Foundation

Technician using electronic leak detection equipment to locate a hidden slab leak

Most Florida homes are built on a concrete slab — and the water lines run underneath it. When one of those lines leaks, you can't see it. Water silently erodes the soil below, damages flooring above, and can even threaten the foundation. Because slab leaks hide so well, knowing the warning signs is your best defense.

What Exactly Is a Slab Leak?

A slab leak is a leak in the pressurized water lines (or sometimes drain lines) buried beneath your home's concrete foundation. Causes include pipe corrosion from mineral-rich Florida water, abrasion where pipes rub against concrete as they expand and contract, poor original installation, and shifting soil. Hot-water lines fail more often because heat accelerates corrosion.

Sign 1: Hot Spots on the Floor

A warm patch on tile or laminate flooring — especially with no heating system running — often means a hot-water line is leaking underneath and warming the slab. Walk barefoot across the ground floor; your feet can detect what your eyes can't.

Sign 2: The Sound of Running Water When Nothing's On

Put your ear to the floor in a quiet house. Hearing water moving when every tap and appliance is off is a classic slab-leak tell. The leak is pressurized, so it runs continuously.

Sign 3: A Water Bill That Keeps Climbing

A slab leak can waste thousands of gallons a month. If your bill spikes with no change in usage — and you've ruled out running toilets and dripping faucets — a hidden leak under the slab is a prime suspect. Our guide to hidden leak warning signs covers the full checklist.

Sign 4: Cracks, Buckling, or Damp Flooring

Water migrating upward damages flooring from below: laminate buckles, tile grout darkens, carpet develops musty spots. New cracks in walls or baseboards can signal soil erosion beneath the foundation.

Sign 5: Low Water Pressure or a Spinning Meter

A significant leak bleeds off pressure before water reaches your fixtures. For a quick test: turn off everything in the house and watch your water meter — if it keeps moving, water is going somewhere it shouldn't.

Why You Shouldn't Ignore It (or DIY the Digging)

Slab leaks get worse, never better. Ongoing erosion can undermine the slab, invite mold, and destroy flooring. But don't start jackhammering on a hunch — random digging is expensive and often misses. Modern electronic leak detection pinpoints the leak's location through the slab using acoustic and thermal equipment, so any slab leak repair opens the smallest possible area.

Suspect a slab leak under your home? Professional detection finds it without tearing up your floors. Call (772) 946-0023.