San Antonio, Texas
Why slabs in this city leak
Builders here pour slabs on grade, often with post-tension cables. Copper or PEX in or under that slab lives in alkaline fill, moisture, and slight movement as clay wets and dries. Copper pits. PEX fittings can be the weak point. Either way, water under a slab does not stay in a polite puddle. It follows the path of least resistance along the bottom of the concrete.
Unrepaired slab leaks waste water, lift tile, feed mold in toe-kicks, and in some cases contribute to differential moisture under a foundation. We are plumbers, not foundation engineers. If the house already has cracks you are watching, say so. We will not diagnose a pier plan on a plumbing page.
Hot-side leaks are easier to feel. Cold-side leaks hide until the bill arrives or a closet smells like a cave. Both deserve a meter test and listening, not a random jackhammer in the hall because that is where the rug is damp.
The working order
Stop the water if it is a blowout. Confirm the leak is under the slab, not a heater, not irrigation, not a toilet. Mark a zone. Discuss spot repair versus reroute. Spot repair opens the slab at the leak. Reroute abandons the bad section and runs a new line in a wall, attic, or shallow trench. The right choice depends on access, the number of leaks, and the finish you are about to break.
We talk about dust, cable locations on post-tension slabs, and whether a small opening is even legal or wise without knowing where tendons sit. That is a safety issue, not a scare tactic.
After the repair, we pressure-test. A slab leak that “seems quieter” is not a pass. The meter has to hold.
- Do not keep the leak “just a little on” so the grass stays green.
- Turn off the heater if the leak is on the hot side and the tank is dry-firing.
- Save meter photos for anyone else who needs the timeline.
Neighborhood patterns
Mid-century houses inside Loop 410 and older cottages toward the missions see more copper stories. Newer north-central and Stone Oak houses see more PEX and manifold stories. Hill Country edge lots in Helotes and Leon Springs add long private lines from a well or a long meter run — those are not always “slab” leaks, but they feel the same on a bill.
If you want official context on building in the city, start at sanantonio.gov and Development Services. Landmark pages such as The Alamo and Missions NHP are for geography, not for claiming we work inside those sites.
What this site will not do
We will not post fake before-and-after job photos, invented reviews, or a license number in the footer. Stock images on this page are labeled. For any contractor, including us once credentials are published, use the TDLR lookup.
If water is entering living space right now, use emergency plumber. If you only know the bill is high, start with leak detection and we will tell you if it became a slab job.
Living on the leak while you decide
Some households keep the water on “just for dishes” while they think about a slab opening. That choice waters the clay under the house. If you must wait for a part, a decision, or a second opinion, keep the house valve closed and use a hose bib or a neighbor for drinking water. Inconvenience is cheaper than a wider wet path.
Finish protection is part of the job even when we have not picked up a saw. Plastic on a doorway, a walkway that is not through the good rug, a plan for dust if we open at all. We will say when a small opening is likely and when a reroute avoids the good tile. You get to choose once you have both prices in your head, not once the saw is already singing.
If a foundation company is already in the conversation, tell us. Moisture under a slab is one input they watch. We will not pretend to be that company. We will also not ignore them if they have asked you to keep a leak off while they measure.
Reroute conversations without the scare music
A reroute abandons a bad underground section and runs a new line where you can see it later — attic, wall, or a shallow trench you chose. It is not an admission that the house is doomed. It is often how people keep a new floor. Spot repair is still right when the leak is local, the finish is modest, and tendons are mapped.
We will price both when we can. We will not pretend they cost the same. Dust, tile match, and time in the house are part of the price even when the pipe itself is short. Write the finish on the form so we do not assume builder carpet.
After either path, the meter has to hold. “It sounds quieter” is not a test. If the leak was hot-side, the heater should be checked so it is not dry-firing. Then you can turn the house back into a house instead of a listening post.