Almost every house in Porter, Spring, Conroe and The Woodlands is built slab-on-grade. No basement, no crawlspace — just a concrete slab poured on the ground with water lines running underneath it.
That works fine until one of those lines fails. And because there's no space under the house for water to be seen collecting, a slab leak can run for weeks or months before anything obvious happens. The soil washes out from under the foundation the entire time.
Why this happens so much around here
Two things, working together.
The soil. Gulf Coast clay is expansive: it swells when saturated in a wet spring and shrinks hard during an August drought. That cycle moves the slab, and anything rigid running beneath it gets stressed at the same points, year after year. Twenty or thirty repetitions of that is a lot to ask of a copper joint.
The pipe. Homes built from roughly the 1970s through the early 1990s typically have copper supply lines under the slab. On our water, copper is susceptible to pinhole corrosion from the inside out. Where a line was laid in direct contact with concrete rather than properly sleeved, abrasion from that seasonal movement finishes the job.
Which is why the neighbourhoods we get called to most for slab leaks are the ones built in that window — Porter Heights, River Plantation in Conroe, much of Champion Forest and Memorial Northwest in Spring, the earlier Woodlands villages, older Kingwood, and the 1960s–70s housing in Oak Ridge North.
The signs, roughly in the order people notice them
A water bill that jumped with no change in how you use water. This is usually the first hard evidence, and it's often dismissed as a billing error for a month or two.
The sound of running water with everything off. Most noticeable at night. People often assume it's a neighbour's irrigation or a toilet running.
A warm patch on the floor. This one is specific and worth acting on immediately — it means the leak is on the hot-water line, and you're heating water that's going into the ground.
Damp carpet, cupping wood floors, or a musty smell confined to one area of the house.
Pressure that dropped everywhere, not at a single fixture.
New cracks in flooring, tile grout or drywall, as soil washes out and the slab loses support. By this stage the leak has been running a while.
The test you can do this afternoon
Turn off every fixture and water-using appliance in the house — taps, ice maker, irrigation, washing machine, dishwasher. Go out to the water meter and note the reading, or watch the small low-flow indicator dial if yours has one.
Wait an hour. Use no water at all during that time. Check the meter again.
If it moved, water is leaving the system somewhere. That doesn't prove it's under the slab — it could be an irrigation line, a hose bib, or a toilet flapper — but it does mean you have a leak, and it's worth having someone find out where.
Finding it without opening the whole floor
This is where the cost is decided. Locating a slab leak properly means isolating the hot and cold systems and pressure-testing them separately to establish which has failed, then using electronic listening equipment and line tracing to narrow the failure to a specific point before any concrete is cut.
Opening a slab on a guess is expensive, and it's frequently in the wrong place. Anyone proposing to start breaking concrete before they've located the leak is proposing that you pay for their guess.
Your three options
Spot repair. Break out a small section of slab, expose the failed line, repair it, restore the concrete and flooring. The cheapest outcome, and the right one when the rest of the system is sound and this is a first occurrence.
Reroute. Abandon that section under the slab and run a new line overhead through the attic and down inside the walls. Often better value when the leak is somewhere awkward to reach, and it permanently removes that run from beneath the concrete.
Repipe. Replace the supply system with Uponor PEX, routed overhead. This is the answer when the house has already had a slab leak or two, because at that point the copper is at the end of its service life generally rather than in one unlucky spot.
A second slab leak within a couple of years is the system telling you which option it wants. The next few individual repairs will usually cost more than doing it once.
Don't sit on it
The reason to move quickly isn't the water bill. It's that a leak under the slab is steadily washing soil out from under your foundation, and foundation work costs considerably more than plumbing does.
If your bill jumped or you can hear water with everything off, we'll come and find out — no service fee, Monday through Saturday, 8am to 8pm. Call (832) 885-9820.