Do I need a plumber for a slab leak?

Yes. A slab leak is licensed-plumber territory, not a DIY repair. The pipe is buried in your concrete slab, so finding it takes specialized leak-detection equipment — acoustic ground microphones, pressure and hydrostatic tests, a sewer camera, thermal imaging — and fixing it carries real structural risk, especially on a post-tension slab where a severed cable can cause structural failure. Cutting into a structural slab and altering plumbing also generally needs a permit. So the leak belongs with a licensed, insured plumber who can detect before demolishing. If the leak has already moved the foundation, you also need an independent engineer — the plumber fixes the pipe, the engineer scopes the structure.

How do I choose a slab leak plumber?

Screen for five things. First, licensed and insured — non-negotiable for any work that cuts a structural slab. Second, real leak-DETECTION capability (acoustic, pressure, hydrostatic, camera, thermal) so they pinpoint the leak BEFORE breaking any concrete. Third, a written detection finding and a demonstration of the leak location before the first piece of slab comes out. Fourth, experience with under-slab and post-tension slabs — post-tension cables must be scanned before any cutting. Fifth, a clear repair-options conversation: spot repair versus reroute or repipe versus trenchless versus tunneling, matched to your situation rather than the one method they prefer to sell. A plumber who reaches for the jackhammer 'to find it' fails the test.

Can a plumber find a slab leak without breaking concrete?

Yes — that is the entire point of modern detection, and it is what separates a slab-leak specialist from a generalist with a jackhammer. Acoustic listening, pressure testing, hydrostatic testing, sewer-camera inspection, infrared, and tracer gas are all non-destructive or work from existing access points like a cleanout. Done well, they pinpoint the leak so the plumber opens one small square of concrete directly over it, instead of breaking up a floor to search. A plumber who wants to start breaking concrete to locate the leak has it backwards: detection finds it, demolition only reaches it. Our detection guide covers each method.

Should a plumber detect the leak before breaking the slab?

Always. Detection comes before demolition — it is the cardinal sequencing rule, and the single biggest red flag is a plumber who wants to start breaking concrete to 'find' the leak. Detection runs roughly $150–$600 of acoustic, camera, pressure, and hydrostatic work and pinpoints the leak so only a small section of slab is opened, rather than a whole floor. On a post-tension slab the location must be scanned before any cutting, because a severed cable can cause structural failure. Insist on a marked, demonstrated leak location before any concrete moves; a plumber who skips that step is gambling with your slab and your wallet.

How much does a slab leak plumber cost?

It comes in two parts. Detection — finding the leak — runs about $150–$600, with the slab-leak-specific average near $280, and it is the cheapest, highest-leverage money on the project because it keeps the demolition small. The repair that follows is the larger number: a single spot repair runs roughly $250–$850 per pipe, a reroute $600–$4,000, and a whole-house repipe $4,000–$15,000, with the national slab-leak repair average around $2,280–$2,300 (range roughly $630–$6,750, per 2025–2026 HomeAdvisor and Angi data). These are industry-estimate planning ranges, not quotes — get on-site bids. Our cost page breaks down every line.

Do I need a plumber or a foundation company?

For the leak itself, a plumber — and you fix the leak first. A slab leak is a plumbing failure, and the cardinal rule is to repair the pipe before any structural foundation work, because piering or re-leveling over an unfixed leak just stabilizes soil the water will move again. Often, fixing the leak is the whole repair: once the water is gone, the soil restabilizes and no structural work is needed. If the leak has already moved the foundation — new cracks, sticking doors, sloping floors — you need both, in order: the plumber fixes the pipe, then an independent licensed engineer scopes the structure after elevations are re-surveyed. The foundation company comes last, and only for what is still out of tolerance.

What about a post-tension slab?

A post-tension slab demands extra care, and it is a direct question to ask any plumber before hiring. These slabs are reinforced with steel cables held under enormous tension; cutting one to reach a pipe can cause structural failure. So on a post-tension slab the leak location must be scanned or X-rayed before any cutting, to map the cables so the cut lands clear of them. A qualified slab-leak plumber will know this, ask whether your slab is post-tension, and arrange scanning as a matter of course. One who is ready to jackhammer without scanning is exactly the plumber to walk away from — this is non-negotiable, not optional.

Is a slab leak an emergency?

Treat it as one. A slab leak does not stay still: escaping water can wash out the soil that supports your foundation and, per US EPA guidance, spawn mold within 24–48 hours of water intrusion. The right immediate response is to shut off the main water supply and call a licensed plumber or leak-detection specialist promptly. Acting fast limits the water damage, protects any insurance claim, and keeps a plumbing problem from becoming a structural one — because the cheapest version of this repair is always the one done before the water reaches the soil.

Is a slab leak covered by insurance?

Sometimes, and narrowly — and it does not change who you call first. Standard homeowners insurance often covers a sudden, accidental pipe burst, including the tear-out to reach and replace the slab and the resulting water damage to floors and walls, but typically not the broken pipe itself. It excludes gradual leaks, long-term seepage, corrosion and wear-and-tear, and earth movement or settling. Per the Insurance Information Institute (Triple-I), water damage is a top homeowners claim, so carriers scrutinize cause closely. Either way, call a licensed plumber to fix the leak and document everything; if the foundation moved, an independent engineer's cause-of-loss report is what the claim turns on.

Slab Leak Plumber: How to Choose One (2026)

A slab leak needs a licensed plumber with leak-DETECTION gear — not a guy with a jackhammer. The pipe is buried in your concrete slab, so the job is to find it before anyone breaks concrete: a good slab-leak plumber pinpoints the leak with acoustic, pressure, hydrostatic, and camera tools, then opens one small square of slab directly over it. The plumber who reaches for the jackhammer "to find it" has the order backwards, and on a post-tension slab that mistake can cause structural failure. This page is about choosing the right plumber — what to demand, the questions to ask, and the one case where you also need an engineer. How the leak is found, how it is fixed, and what it costs each have their own page; we summarize and link, and stay in our lane here: picking the plumber. For the full subject, start with the slab-leaks overview.

Why this is plumber work, not DIY

A slab leak is one of the clearer cases where a homeowner should not pick up the tools. A slab leak is licensed-plumber territory — specialized leak-detection equipment, structural risk, permits — NOT DIY. Four reasons compound.

Specialized detection equipment. The pipe is hidden in concrete, so locating it takes acoustic ground microphones, pressure and hydrostatic tests, a sewer camera, and thermal imaging — gear and trained interpretation a homeowner does not have. Get the location wrong and you open the slab in the wrong place.
Structural risk. Cutting into a structural slab to reach a pipe can weaken the foundation if done blind, and a botched attempt — a missed second leak, soil left unsupported — can cause damage far costlier than the original leak.
Permits. Cutting a structural slab and altering plumbing generally requires a permit, and unpermitted structural work can quietly void warranties and complicate a future sale.
Post-tension cables. Many slab homes are reinforced with post-tension cables — steel tendons held under enormous tension inside the concrete — and cutting one 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.

The leak belongs with a licensed plumber. Any movement of the foundation belongs with an independent licensed engineer — not the contractor selling the fix. For the cause behind the leak, see our plumbing-leaks page.

What to look for in a slab-leak plumber

The right plumber is defined less by price than by capability — specifically, the ability to find the leak before breaking concrete. Read down this checklist and you can tell a slab-leak specialist from a generalist with a jackhammer.

Criterion	Why it matters
Licensed and insured	Non-negotiable for any work that cuts a structural slab; protects you if something goes wrong, and a baseline of accountability
Leak-DETECTION capability (acoustic, pressure, hydrostatic, camera, thermal)	So they pinpoint the leak BEFORE breaking concrete — the single most important thing a slab-leak plumber brings; a plumber without it can only search by demolition
Written detection finding and a demonstration of the leak location	Proof the leak was actually located, not guessed; insist on seeing the marked spot before any concrete comes out
Experience with under-slab and post-tension slabs	Post-tension cables must be scanned before any cutting — a severed cable can cause structural failure; a qualified plumber asks whether your slab is post-tension and scans as a matter of course
A clear repair-options conversation (spot repair vs reroute or repipe vs trenchless vs tunneling)	Honesty that the method should fit your situation — number of leaks, access, whether you keep your floors — rather than the one method the plumber prefers to sell

What to demand in a slab-leak plumber. The thread running through all five is the same: find the leak before breaking concrete, and prove it.

The one criterion that decides the rest is the second: detection capability. A plumber who cannot pinpoint the leak has only one tool left — breaking concrete to search — and that is precisely the approach this whole subject is built to avoid.

Detect before you demolish

This is the rule to insist on, and it is worth stating plainly: detect before you demolish. A good slab-leak plumber confirms the leak and pinpoints it — with acoustic listening, a pressure or hydrostatic test, a sewer camera, infrared, or tracer gas — before any concrete is broken, so only a small section of slab is opened directly over the leak. Detection runs roughly $150–$600 and routinely prevents thousands in unnecessary slab-breaking; the slab-leak-specific average is near $280. That is the cheapest, highest-leverage money on the entire project, and it is the line item that keeps the demolition small.

So make it a hard requirement: ask the plumber to pinpoint the leak and demonstrate its location before the first piece of slab comes out. A plumber who wants to start breaking concrete "to find it" has the sequence backwards — detection finds the leak, demolition only reaches it. This page summarizes the demand; the mechanics of each method, how a specialist sequences them, and the post-tension scanning requirement live on the dedicated detection guide.

The repair conversation

Once the leak is pinpointed, a good plumber walks you through the options rather than defaulting to one. There are several common ways to fix a slab leak, and the right one turns on how many leaks there are, where they sit, the pipe's condition, and whether you want to keep your floors:

Spot repair — one isolated, locatable leak in a system that is otherwise sound. Cheapest and most targeted.
Reroute or repipe — multiple leaks or widespread corrosion; abandon the failing slab line and run new pipe overhead through walls and the attic.
Trenchless lining — a structurally sound drain line with cracks or root intrusion, repaired from the inside with no digging.
Tunneling — reach the pipe from outside to keep your floors intact and stay in the home.

The rule worth committing to memory: if you have already spot-repaired two or three leaks on the same line, stop chasing and reroute or repipe — each spot repair on a deteriorating pipe only buys time until the next pinhole. A plumber who keeps selling you the third spot repair on a dying line is not doing you a favor. The method-by-method decision logic and the tunneling-versus-breaking-the-slab tradeoff live on the repair guide, and what each option runs is on the cost page.

When you also need an engineer

A plumber fixes the pipe — but a plumber does not diagnose your foundation. If the leak has already moved the slab, you need a second professional, and the order is fixed: the plumber fixes the leak first, then an independent licensed Professional Engineer scopes the structure. The two roles do not overlap. The plumber's job is the plumbing; the engineer's job is the elevation survey, the cause-of-loss read, and the underpinning spec if one is needed.

How do you know the foundation may have moved? The telltale signs are new cracks, doors that have started to stick, and floors gone out of level. When those appear alongside a slab leak, do not stop at the plumbing test — fix the leak first, let the soil settle, re-survey the elevations, and only then stabilize whatever is still out of tolerance. Hire your own engineer rather than relying on a contractor's, and budget $500–$1,500 for the report. For the document itself and what it establishes, see our engineer-report coverage.

FAQ Note

The FAQ below answers what San Antonio homeowners ask most when choosing a slab-leak plumber — whether you need one at all, how to pick one, whether a plumber can find the leak without breaking concrete, whether detection should come before the slab is opened, what it costs, whether you need a plumber or a foundation company, what to do about a post-tension slab, whether a slab leak is an emergency, and how insurance fits. For how the leak is found, see detection; for how it is fixed, repair; for what it costs, cost; and for the cause behind it, the plumbing-leaks page.

Get Matched With a Vetted San Antonio Slab-Leak Plumber

If you have a slab leak and need a plumber, the right one finds the leak before breaking concrete — not a sales pitch to start jackhammering. We'll match you with a vetted San Antonio slab-leak specialist who detects before they demolish, and point you to an independent engineer if the foundation may have moved. The match is free, the quote is no-obligation, and we don't take a fee from you. We screen for licensed-and-insured crews, confirm-then-pinpoint detection (a hydrostatic or pressure test before any cutting), a demonstrated leak location, post-tension scanning where the slab calls for it, and an honest repair-options conversation rather than a default jackhammer. If a quote skips detection and reaches for the concrete, we'll tell you — because on a slab home, finding the leak is the job, and breaking concrete is only how you reach it.

Slab Leak Plumber: How to Choose the Right One