Slab Leak Repair Cost

A slab leak is a leak in a water or drain line running under a concrete foundation. Angi puts the national average repair at $2,280, including leak detection, with most homeowners paying $630 to $4,400. Where the leak sits drives most of the price: Angi's example of an easy leak under an unfinished utility closet cost about $630, while a hard-to-reach leak under kitchen cabinets cost about $4,400.

Leak detection

Before any repair, a plumber locates the leak with acoustic or pressure equipment. Angi lists detection at $150 to $400, about $280 on average.

Cost by repair method

Direct access means cutting through the floor, fixing the pipe and patching the concrete. It is fast for a single leak but disturbs flooring. Rerouting abandons the leaking line and runs a new one through walls or the attic. It avoids breaking the floor and is often chosen for older pipes likely to leak again. When many lines are failing, a whole house repipe may make more sense.

Cost by leak type

Floor and foundation repair

After the pipe is fixed, the opening needs to be closed and finished. Angi lists build-back at around $500 on average, with a range of $300 to $10,000 or more when finished flooring or kitchen cabinets sit over the access point. Concrete slab repair after the leak fix costs $300 to $6,750. If the leak damaged the foundation, a structural engineer runs about $150 per hour.

Signs of a slab leak

• A water bill that rises without a change in use.
• The sound of running water when everything is off.
• Warm spots on the floor (hot water line).
• Damp carpet, warped flooring or cracks in tile.

Insurance

HomeGuide notes homeowners insurance may cover slab leak repairs when the leak was caused directly by a covered event. Policies vary, so check yours before work starts and keep the detection report.

Other costs

Permits run $75 to $200 (Angi). Water damage cleanup can range from $500 for minor subfloor damage to $15,000 or more. Acting quickly on a suspected leak keeps that number down. If water is spreading, see emergency plumber cost.

What a slab leak is

A slab leak is a leak in a water line that runs under or within a concrete slab foundation. Pipes can wear through from friction against concrete, corrode, or crack when the slab moves.

More on signs of a slab leak

• A water bill that rises without explanation.
• The sound of running water when everything is off.
• Warm spots on the floor, from a hot water line leak.
• Damp or stained flooring, or cracks that appear suddenly.
• Low water pressure.

How leaks are found

Leak detection specialists use pressure testing, acoustic listening equipment and sometimes thermal imaging to pinpoint the leak before anyone cuts into the floor. Accurate detection keeps the repair area small.

Repair options

• Direct access. Break through the slab at the leak, repair the pipe and patch the concrete. Best for a single, isolated leak.
• Reroute. Abandon the leaking line and run new pipe through walls or the attic. Avoids breaking the slab and is often recommended for older pipes.
• Repipe. If the lines under the slab are failing in several places, replacing the plumbing may be the most lasting fix.
• Epoxy lining. Some companies line the pipes from inside; it is not suitable in every situation.

What affects the price

Leak detection, the repair method, flooring removal and replacement, and any water damage cleanup all add to the total. Breaking through tile or hardwood is more expensive to restore than carpet or concrete.

In Texas

Slab-on-grade foundations are common in Texas, and expansive clay soils make slabs move as moisture changes. That movement is a frequent cause of slab leaks. Homeowners policies often treat access to the leak, the pipe repair and the resulting water damage differently, so it is worth checking what yours covers.

Questions to ask before you choose a repair

1. Where exactly is the leak, and how was it located?
2. Is this the first leak, or is there evidence of others in the same piping?
3. What are the options: spot repair, reroute or repipe, and what does each cost?
4. What floors will be opened, and who restores them?
5. Will the repair require a pressure test or inspection afterward?
6. What does the warranty cover, and for how long?

Why spot repairs sometimes fail

A single slab leak is often a sign that the pipes under the floor are aging. Fixing one leak through the slab stops that leak, but nearby sections may fail later. That is why many plumbers suggest a reroute when the piping is old or the home has had more than one leak. Running new lines through the walls or attic abandons the old under-slab piping entirely.

Insurance and documentation

Homeowners policies often treat the leak and the damage differently. Many cover water damage to floors and walls and the cost of breaking into the slab to reach the pipe, but not the pipe repair itself. Keep the leak detection report and photos of the damage, and call your insurer before major work starts so an adjuster can see it.

Reducing the chance of another leak

High water pressure strains every pipe in the house, including the ones under the slab. A plumber can test the pressure at a hose bib in a few minutes. If it is high, a pressure-reducing valve protects the plumbing. Very hot water lines also fail more often than cold lines, so keeping the water heater at a moderate setting helps too.