Slab Leak Repair: The Six Ways It's Fixed and How to Choose

Once a slab leak is pinpointed, there are six ways to fix it — spot repair, reroute or repipe, trenchless lining, pipe bursting, tunneling, or breaking the slab — and the right one depends on how many leaks you have, where they are, the pipe's condition, and whether you want to keep your floors. The rule that sits underneath all six is the one homeowners break most often: fix the leak before you touch the foundation. Drive a pier under a slab that a leak keeps re-wetting and you are stabilizing soil that will move again. This page is about the repair options — how each one works, when it is the right call, and the access tradeoff that decides whether your floors survive. Finding the leak is a separate step with its own page; so is what it all costs. We summarize and link both, and stay in our lane: repair.

The six repair options, compared

These are the six methods a plumber or foundation specialist chooses among once detection has located the leak. None is universally best. Each fits a specific combination of how many leaks there are, the pipe's condition, and how much interior disruption you will accept. Costs are industry-estimate ranges that vary with region, access, and the number of leaks.

For national context, slab-leak repair averages around $2,280 with a range of roughly $630–$6,750, per 2025–2026 cost data from HomeAdvisor, Angi, and This Old House — a span that runs from a single spot repair to a full reroute. For the detailed cost breakdown by method and the variables that move the number, see our slab-leak cost page. For how the leak is located in the first place — acoustic, infrared, pressure, hydrostatic, and camera methods — see slab-leak detection.

How to choose

The table lays out the options; this is the decision logic. Read down the list and the first line that describes your situation is usually your method.

• A single, locatable leak in a sound system → spot repair. One pinhole or one broken joint, with the rest of the line in good shape, does not justify replacing anything. Access it and fix it.
• Multiple leaks, widespread corrosion, or an aging line → reroute or repipe. When the problem is the pipe itself rather than one bad spot — an old copper, galvanized, or polybutylene run that keeps failing — chasing individual leaks is a losing game. Abandon the slab line and run new pipe overhead.
• A structurally sound drain line with cracks or roots → trenchless lining. If the pipe still holds its round shape, a cured-in-place liner restores it from the inside with no digging.
• A collapsed or ovalized drain line → pipe bursting. Once a line has lost its shape, it cannot be lined; bursting pulls a new HDPE pipe through the old path.
• You want to keep your floors → tunneling. Reaching the pipe from outside keeps every bit of the mess out of the house.
• The floors are coming up anyway → break the slab. If you are already replacing flooring, the most direct route down to the pipe is also the cheapest.

The one rule worth committing to memory cuts across all of these: if you have already spot-repaired two to three slab leaks on the same line, stop chasing and reroute or repipe. Each spot repair on a deteriorating pipe buys a little time until the next pinhole, and the running total quietly passes what a reroute would have cost — except you have also paid to open the slab two or three times to get there. Recurring leaks are the system telling you the pipe is done.

Access: tunneling versus breaking the slab

For supply-line leaks especially, the method question often narrows to one tradeoff: how do you physically get to a pipe buried under concrete? There are two answers, and they sit at opposite ends of the interior-disruption scale.

Breaking the slab comes down through your floor. The crew jackhammers a section of concrete directly above the leak, fixes the pipe, and patches the slab. It is the most direct path and can be the cheapest, and a plumber can usually start the same day. The cost is everything that comes with opening concrete inside a living space: noise, concrete dust through the house, a room that may be unusable for the duration, and flooring that almost always has to be replaced on top of the slab patch. It shines in exactly one case — a single, easy-to-reach interior leak, or floors that are being replaced anyway.

Tunneling comes in from outside. The crew excavates a tunnel under the foundation to reach the pipe from below, so the jackhammering, the dust, and the demolition all stay outdoors. Your floors are untouched, you can usually keep living in the home, and the approach can even allow soil support to be pumped back under the slab while the tunnel is open. The tradeoffs are price and time — roughly $300–$500 per linear foot and one to five days of digging — and the fact that many plumbers simply do not do it. It is the method of choice when the flooring is expensive or intact, when the home is occupied, or for a rental you cannot easily vacate.

There is a hard safety gate in front of either one. Many slab homes are reinforced with post-tension cables — steel tendons held under enormous tension inside the concrete. Cutting one to reach a pipe can cause structural failure. Before anyone jackhammers or cores a post-tension slab, it has to be scanned or X-rayed to map the cables so the cut lands clear of them. This is not optional, and it is one of the central reasons slab-leak repair is not a do-it-yourself job.

Fix the leak BEFORE the foundation

This is the cardinal rule, and it is the one most often violated on slab homes: repair the plumbing before any structural stabilization, or the movement continues. A slab leak and foundation movement are tied together. The escaping water wets the expansive clay under one part of the slab — swelling it into a dome, or washing soil out from under it so that spot settles — and that differential movement is what cracks the slab, the brick, and the finishes. (For how a leak actually moves a foundation, our plumbing-leaks cause page walks the mechanism.)

The consequence for sequencing is absolute. If you pier or re-level a foundation while the leak is still running, you are stabilizing soil that the water will keep moving. The piers are seated correctly and the slab still shifts, because the cause was never addressed. The correct order is: fix the leak first, let the soil settle, re-survey elevations, then underpin only what is still out of tolerance. Often, fixing the leak is the whole repair — once the water source is gone, the soil restabilizes and no structural work is needed at all.

When movement has gone beyond what tolerance allows and the foundation does need stabilizing, that structural fix is a separate scope with its own engineering. Deep underpinning — piers driven through the active soil zone to competent strata — is covered in our underpinning guide. The point here is only the order: the plumbing is fixed first, every time.

Insurance and tear-out

Whether any of this is covered turns on one distinction: sudden versus gradual. A sudden, accidental pipe break — a supply line that bursts — is often a covered peril, and in that case dwelling coverage may pay to tear out and replace the slab to reach the pipe and to repair the resulting water damage to floors and walls. What it generally will not pay for is the broken pipe itself, and it will not pay at all for a gradual leak, long-term seepage, corrosion and wear, or earth movement and settlement — the exclusions that knock out the large majority of Texas foundation claims by cause.

That is why the cause finding matters more than any estimate. Insurers routinely send an adjuster or engineer to determine whether a leak was sudden or ongoing; if it reads as gradual, the seepage and wear-and-tear exclusion ends the claim. Per the Insurance Information Institute, water damage and freezing is the second-most-frequent homeowners claim — so these claims are scrutinized closely. There is a clock on it, too: mold can develop within 24–48 hours of water intrusion, per US EPA guidance, so shutting off the water and documenting the damage fast protects both the claim and the house. The full claim workflow — what to document, the order to do it in, and the role of a sealed engineer's report — is on our insurance guide.

Why this isn't DIY

Slab-leak repair is one of the clearer cases where a homeowner should not pick up the tools, for four reasons that compound.

• Post-tension cables. Cutting one tensioned steel tendon to reach a pipe can cause structural failure. A homeowner has no way to map them; the slab must be professionally scanned before any cut.
• Specialized equipment. Pinpoint detection, trenchless lining and bursting rigs, and tunneling all require gear and training a homeowner does not have, and getting the leak location wrong means opening the slab in the wrong place.
• Permits. Cutting into a structural slab and altering plumbing generally requires a permit, and unpermitted structural work can quietly void warranties and complicate a future sale.
• Structural risk. A botched attempt — a missed second leak, a slab cut that weakens the foundation, soil left unsupported under a tunnel — can cause damage far costlier than the original leak.

The repair belongs with a licensed plumber. Any movement of the foundation belongs with an independent licensed engineer — not the contractor selling the fix.

FAQ Note

The FAQ below answers what San Antonio homeowners ask most once a slab leak is confirmed and the question turns to fixing it — how it is repaired, which method is best, reroute versus repair, what rerouting is, whether the floor has to come up, how long it takes, and the order of operations. For how the leak is located before any of this, see slab-leak detection; for what it costs, the cost breakdown; and for the full picture of how leaks and foundations interact, the slab-leaks overview.

Get Matched With a Vetted San Antonio Slab-Leak Specialist

If a slab leak has been confirmed and you are deciding how to fix it — spot repair versus reroute, tunneling versus breaking the slab, or whether the foundation needs anything at all once the leak is gone — we'll match you with a vetted San Antonio specialist and point you to an independent engineer for any movement of the foundation. The match is free, the quote is no-obligation, and we don't take a fee from you. We screen for the right sequence above all: leak fixed first, post-tension slabs scanned before any cut, and structural work scoped by a sealed engineer only on what is still out of tolerance after the water is off — because on a slab home, fixing the foundation before the leak just guarantees you pay again.