DiagnosticsLeak or Water Damage
Slab Leak Signs in Austin Homes — and Why They Happen Here
Central Texas houses are mostly slab-on-grade: the supply and drain lines run in or under the concrete. East of I-35 that slab sits on expansive Blackland clay that swells when wet and shrinks in drought, flexing the foundation and every pipe in it. West, it’s rocky limestone that abrades pipe. Either way, slab leaks are a regional fact of life.
Signs of a slab leak — supply side
- A water bill that climbs with no change in how you use water.
- The meter runs with every fixture in the house off.
- Warm spots on a tile or wood floor — a hot-water line leaking under it.
- The sound of running water when nothing is on.
- Low pressure that appeared without a city-side cause.
- Damp carpet, cupped hardwood, or white chalky (effloresced) grout lines.
- Cracks in floor tile or the slab that arrived with moisture.
Signs of a slab leak — drain side
- A persistent sewer smell with no obvious source.
- Drains that are slow across the house, then fine, then slow again.
- Soft or heaved spots in the floor.
- Roaches or other insects appearing from floor cracks — they follow moisture and sewer gas.
- Foundation movement — doors that stop latching, fresh drywall cracks — that a foundation company traces to a wet spot.
Why Austin gets so many
Soil movement stresses every joint. Copper set directly in a slab can pit where it reacts with concrete and soil. Hard water and high pressure add wear. And a large share of the area’s 1960s–1990s housing is now at the age where those factors add up at once.
How a slab leak is found and fixed
- Detection first: acoustic listening, pressure testing and thermal imaging locate the leak so the slab is opened once, in the right place — never by exploratory jackhammering.
- Spot repair: open the slab over the leak, replace the section, patch the concrete.
- Reroute: abandon the failed line in the slab and run a new one through the attic or walls — often the smart choice on an older copper system with one leak now and more coming.
- Repipe: when several lines are failing, replace the system (see our repiping guide).
- Drain-line repairs may be trenchless (lining) or tunneled under the slab from outside to avoid tearing up finished floors.
What to do right now
If the meter is moving with everything off, shut the main to stop the water and call. A supply-side slab leak is emergency-adjacent — every hour it runs is water under your foundation.
A rising bill plus a moving meter is the classic slab-leak signature. Get it located properly before anyone opens concrete — detection is cheap compared to a wrong hole.