Why Austin gets so many slab leaks
Almost every Austin home sits on a concrete slab, with copper or PEX water lines running through or beneath it. Under that slab is Central Texas clay — soil that swells dramatically when wet and shrinks when dry. Our long, hot summers followed by sudden downpours put foundations through an annual expansion-contraction cycle, and every cycle flexes the pipes embedded in the concrete.
Copper doesn't like flexing. Over years, the movement abrades pipes where they contact concrete or rebar, and stress concentrates at bends and joints until a crack opens. That's the mechanics of nearly every slab leak we find: not a dramatic failure, but decades of microscopic movement finally winning. Homes built from the 1960s through the 1990s with copper under the slab are the prime candidates — they're old enough to have endured thousands of soil cycles.
Sign 1A water bill that jumped for no reason
The most common first clue. A slab leak can waste thousands of gallons a month with zero visible water — the bill is often the only early warning. Compare against the same month last year, not just last month.
Sign 2Warm or hot spots on the floor
A hot-water line leaking under the slab heats the concrete above it. Walk barefoot: a patch of floor that's noticeably warmer than the surrounding area is a classic hot-side slab leak signature.
Sign 3The sound of running water when everything is off
Stand quietly near the slab in the middle of the night with all fixtures off. A hiss or rush you can't source to any appliance is water escaping under pressure — and it's not subtle once you listen for it.
Sign 4Damp carpet, buckling wood, or mysterious moisture
Water migrates upward through concrete. Carpet that stays damp in one spot, laminate that cups, or tile grout that darkens in a pattern can all trace back to a leak below.
Sign 5Low water pressure, especially hot
A leak is an open exit in a pressurized system — pressure drops everywhere downstream. If your hot water pressure has faded and there's no other explanation, the hot line under the slab is suspect number one.
Sign 6Mold, mildew, or musty smells near the floor
Persistent moisture under flooring breeds mold where you can't see it. A musty smell concentrated at floor level, or mold appearing along baseboards, means water has been there a while.
Sign 7Cracks in the slab, walls, or a shifting floor
The late-stage sign. Escaping water erodes supporting soil unevenly, and the slab settles into the void. New cracks in tile, sticking doors, or a floor that feels subtly uneven deserve immediate attention — this is foundation territory.
The 60-second test you can do today
Turn off every faucet, appliance, and irrigation zone in the house. Go to your water meter and watch the leak indicator (the small triangle or star on the dial) for fifteen minutes. If it moves at all, water is leaving your system somewhere it shouldn't. Combine that with any sign above and you have your answer — call us before the next billing cycle, not after.
How professional detection works
Once you call, we confirm and locate in a single visit. First, pressure testing: we isolate the hot and cold systems and watch which side loses pressure — that tells us which line is leaking. Then acoustic listening equipment picks up the distinct sound of pressurized water escaping, letting us triangulate the leak to within inches through the slab. For hot-side leaks, thermal imaging shows the heat bloom in the concrete. You'll see the evidence yourself before we discuss a single repair option.
Repair options, from least to most invasive
- Spot repair through the slab. Open a small section of floor directly over the leak, repair the pipe, patch the concrete. Fastest when the leak is isolated and the system is otherwise healthy — but it leaves the rest of the aging line in place.
- Reroute overhead. Abandon the under-slab line and run new PEX through walls and attic. No concrete demolition, often similar cost to a slab penetration, and the new line is accessible forever. Our most common recommendation.
- Tunneling. Dig under the slab from outside to reach the leak. Preserves interior flooring — worth considering with expensive tile or wood — but it's labor-intensive.
- Whole-house repipe. When the system has produced multiple leaks or the pipe is at end of life, replacing everything ends the cycle. Often paired with a remodel for efficiency.
The honest conversation we have with every slab-leak customer: one leak in a 25-year-old copper system is an event; the second is a pattern. We'll price the spot fix and the permanent fix side by side so you can decide with real numbers. For the full picture on finding any hidden leak, see our Austin leak repair page.
