A slab leak happens when a water supply or drain line running beneath your home's concrete foundation develops a leak. They're most common in Sun Belt states — Texas, Arizona, Florida, Oklahoma — where shrink-swell clay soils shift seasonally, stressing copper pipes embedded in the slab. Catching one early is critical: undetected slab leaks cause mold, foundation damage, and water bills that can spike by hundreds of dollars per month.
8 Signs You May Have a Slab Leak
1. Warm or hot spots on the floor (a hot water line is leaking beneath). 2. The sound of running water when all fixtures are off. 3. Water bill spikes of 20–50% without a usage change. 4. Cracks in walls or flooring (foundation movement from water intrusion). 5. Damp or wet carpet, especially near exterior walls. 6. Mold or mildew smell in rooms at floor level. 7. Low water pressure throughout the house. 8. Your water meter continues spinning when all water is turned off.
Slab Leak Repair Options and Costs
Spot repair ($500–$2,500): Works for a single isolated leak in an accessible location. The plumber cuts through the concrete, repairs the pipe section, and patches the slab. Best when leaks are infrequent and pipes are otherwise in good condition. Pipe rerouting ($2,500–$6,000): Bypasses the leaking section by running a new pipe above the slab through walls and/or attic space. Avoids concrete cutting and is ideal when pipes are generally deteriorating. Epoxy pipe lining ($3,000–$8,000): A trenchless repair that coats the interior of existing pipes with epoxy resin, sealing small leaks without excavation. Most cost-effective for widespread small leaks.
Austin, TX homeowners: Slab leaks are especially common in Austin due to shrink-swell clay soils over limestone bedrock. Find licensed slab leak specialists at provenquote.com/plumbing/austin-tx.