Slab Leak FAQ

A slab leak is a water leak occurring in the pipes that run beneath or through your home's concrete foundation slab. The term typically refers to failures in hot and cold water supply lines, though drain lines under the slab can also leak. Because the pipes are not visible, the leak reveals itself through indirect symptoms rather than direct observation.

Slab leaks are relatively common in Fort Worth and throughout North Texas for two main reasons: the Blackland Prairie clay soil that expands and contracts significantly with moisture changes (creating mechanical stress on under-slab pipes), and the large inventory of homes built in the 1950s–80s with original copper supply lines that are approaching or past their service life. The combination of aging pipe and challenging soil conditions makes Fort Worth an area with elevated slab leak frequency.

The main causes include: soil movement stressing the pipe, age-related corrosion of copper pipe from inside or outside, thermal cycling fatigue in hot-water lines (from repeated expansion and contraction), installation factors (kinked pipe, direct concrete contact), and electrolytic corrosion where dissimilar metals meet. See the full guide: What Causes Slab Leaks.

Common indicators include: an unexplained increase in your water bill, a specific area of your floor feeling warm (hot-line leak), the sound of running water when all fixtures are off, damp or buckling flooring with no visible source, and cracks in walls or flooring following a straight line. See the full guide: Slab Leak Symptoms.

You can perform a basic check: shut off all water use in the house and check your water meter. If the meter is moving with all water off, you have a leak somewhere. You can also listen at floor level with all water off for the sound of running water. However, confirming the leak is in the under-slab plumbing and locating it requires professional pressure testing and detection equipment.

Hydrostatic pressure testing is a diagnostic procedure that checks whether your plumbing lines hold pressure. Each line is isolated and pressurized; a line that drops pressure has a leak somewhere along its run. It's the first step in slab leak diagnosis — it confirms the leak exists and identifies which line is affected before acoustic detection is used to locate it.

A typical detection visit — pressure testing plus acoustic or electronic location — takes 2–4 hours. More complex situations may take longer.

The three main approaches are: (1) Spot repair — targeting the specific leak location by cutting a small opening in the concrete; (2) Pipe reroute — running a completely new supply line through walls or attic space, bypassing the slab entirely; (3) Tunneling — accessing the pipe from below the slab through a horizontal tunnel from the exterior. The right method depends on leak location, pipe condition, slab type, and what makes sense long-term.

A pipe reroute installs a new supply line through wall cavities or attic space — avoiding the slab entirely. The old under-slab pipe is abandoned in place. Rerouting makes sense when: the system has a history of multiple slab leaks, the copper pipe is aging and likely to fail again, the leak location poses post-tension slab cable risk, or interior flooring makes concrete access disruptive.

Not necessarily. A spot repair requires only a targeted cut in the concrete at the confirmed leak location. A reroute requires no concrete cutting at all. Tunneling accesses the pipe from the exterior without disturbing interior flooring. The method that minimizes unnecessary floor disruption depends on where the leak is and which repair approach is appropriate.

Cost varies significantly based on repair method, leak location, slab type, and complexity. Detection work is priced separately from repair. Accurate repair pricing requires knowing the leak location — estimates given without a confirmed leak location are not reliable. See the Slab Leak Cost Guide for a framework.

Coverage varies by policy. Many policies cover the 'access costs' (opening the concrete) and resulting water damage, but not the pipe repair itself. Some policies cover rerouting as a lower-cost alternative to tear-out. Document everything and contact your insurer before cleanup begins.

Neighborhoods with the most slab leak activity tend to be those with older housing stock and Blackland Prairie clay soil. This includes Northside (76106, 76164), East Fort Worth (76112, 76120), South Fort Worth (76119), and parts of central Fort Worth (76101, 76102). Newer neighborhoods with PEX plumbing are less affected.

A post-tension slab is a concrete foundation reinforced with tensioned steel cables running through conduit channels in the concrete. Many Fort Worth homes from the 1970s onward use this construction type. The cables must not be cut — doing so causes serious, expensive structural damage. Any concrete cutting in a post-tension slab requires knowing cable locations first. Rerouting is often the preferred repair option for leaks in post-tension slabs because it avoids any concrete cutting.