A slab leak is not just a repair — it is a decision: tunnel to the leak, reroute overhead, or repipe the house. Nobody owns the framework for making that call. This guide gives it to you: how leaks are found, what each option really costs in disruption and risk, and how to choose.
Slab leaks announce themselves subtly: a hot spot on the floor, the sound of running water when nothing is on, a water bill that jumps for no reason, or a water heater that never stops firing. By the time the signs are obvious, the leak has often been running for weeks.
This guide is for the homeowner deciding what to do and the plumber explaining the options. It covers detection, then the real subject: tunneling vs rerouting vs repiping, compared on the merits instead of by sales pitch.
Slab leak repair involves plumbing code compliance, and any tunneling or excavation near structural elements requires professional evaluation — this guide does not cover structural work. Pre-1978 homes need lead/asbestos testing before disturbing materials. Hire a licensed plumber; this guide helps you understand the options, not replace the pro.
Slab leak work must meet the local plumbing code for any pipe replacement, and tunneling or excavation must not compromise structural elements — structural evaluation belongs to a licensed pro or engineer. Pre-1978 homes need lead/asbestos testing before disturbing materials. Check local amendments for permit requirements.
Start with the meter test: shut off every fixture and watch the water meter — movement means water is going somewhere. Check the water heater for constant firing, feel for warm spots on the floor, and listen for running water in quiet hours. Rule out the easy answers first: a running toilet, an irrigation leak, or a water-heater relief valve can all mimic slab-leak symptoms.
Shut the valves to isolate hot from cold, then pressure-test each side separately — the side that will not hold pressure holds the leak. This halves the search area before any equipment comes out. For homes with a manifold or zone valves, isolate zone by zone. Every isolation step you do with valves is a jackhammer swing you do not take.
Use acoustic listening equipment to pinpoint the leak's location under the slab — a trained ear with electronic amplification can locate within inches. Thermal cameras help enormously on hot-water leaks, showing the warm plume spreading through the slab. Pinpointing is what separates a one-square-foot opening from a exploratory trench across the room.
Before choosing a repair path, map how far the water has traveled with a moisture meter: under flooring, into baseboards, toward walls. The leak point is small but the migration is not, and the repair scope has to cover the damage, not just the pipe. Document everything with photos — for the homeowner, for insurance, and for the permit file.
This is the framework nobody else publishes. Tunnel to the leak when: the system is otherwise young and healthy, the leak is accessible, and it is the first occurrence. Reroute overhead (abandon the slab lines) when: the slab has leaked before, access is difficult, or the homeowner wants the pipe out of the concrete for good. Repipe the house when: there is a pattern of pinholes, the pipe is at end of life, or the math on repeated spot repairs exceeds the repipe cost. Be honest about which situation you are in — the cheapest option today is often the most expensive option by the third leak.
Tunneling means excavating under the slab with proper shoring, repairing the pipe section, backfilling, and compacting — never undermining load-bearing elements without engineering review. Rerouting means running new overhead lines through walls and ceilings to bypass the slab entirely, abandoning the old lines in place. Repiping means the full whole-house sequence. Whichever path, pressure-test the repair before closing anything.
Standing water and wet materials need professional drying — dehumidifiers and air movers, not hope. Wet drywall, insulation, and flooring that stayed wet grow mold; remove and replace what cannot be dried. This phase often costs more than the pipe repair itself, which is why the moisture mapping in step 4 matters: the restoration scope should never be a surprise.
If you tunneled or spot-repaired, tell the homeowner honestly what the system age means for future leaks and what the trigger for a repipe should be. If the water chemistry is aggressive (low pH, high chloramines), address it — water treatment extends the life of whatever pipe remains. A leak repair without a forward plan is just scheduling the next emergency call.
Slab leak repairs often involve an insurance claim, and claims live or die on documentation. Photograph every stage: the initial damage, the moisture meter readings, the pinpointed location, the opened slab, the repaired pipe, and the restoration. Keep the pressure-test results, the acoustic location report, and all invoices organized. Homeowners should notify their carrier early — sudden water damage is typically covered, while long-term seepage often is not, and your documentation is what proves which one it was.
Every one of these has cost someone a callback. Learn them here instead of on the job.
Breaking slab on a guess destroys flooring and often misses the leak. Acoustic location first, concrete second.
The third pinhole in aging copper means the system is failing, not the fitting. Know when the pattern says repipe.
The leak point is small; the water migration is not. Map the moisture before deciding the repair scope.
Undermining structural elements without engineering evaluation. Tunneling has structural limits — respect them.
Repairing today's leak with no strategy for a system that will leak again next year. The decision framework below exists for exactly this.
Slab leak repairs often turn into repipes — and repipes turn into copper. A single spot repair yields a few feet of pipe; a reroute or repipe pulls the whole failing system out of the slab's reach. That old copper does not belong in the debris pile.
Keep the pulled copper separate and clean. No minimums — every bucket counts. When the job is done, call Sonny at 312-880-8174.
No minimums — every bucket counts. On bigger lots, we handle the freight so you don't lift a finger.
Work to code. Hire a licensed pro where required. This guide explains how the work is done — it does not replace training, apprenticeship, or a license.