Slab Leak Detection & Repair in Alpharetta, GA
Most Alpharetta homes built 1985–1998 sit on slab-on-grade foundations over expansive clay soil. Thirty years in, slab leaks are one of the three highest-volume calls we run. Acoustic and thermal pinpoint detection, then spot repair, rerouting, or epoxy lining — your call after we show you exactly what's down there.
If your water bill jumped without an obvious cause, a section of your floor feels noticeably warmer than the rest, or you can hear water moving inside the slab when every fixture is off — those are the textbook three symptoms of a slab leak, and they're the ones we hear most often from North Fulton homeowners. The cost gap between catching one early and catching one late is large, which is why diagnostic accuracy matters more than speed on this particular service line.
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What a slab leak actually is, and why Alpharetta sees so many
A slab leak is a water leak in one of the copper supply lines that runs underneath the concrete foundation of your home. In Alpharetta and most of North Fulton, homes built between roughly 1985 and 1998 — the big subdivision wave that gave us Windward, Webb Bridge, Brookwood, much of Old Milton — were built slab-on-grade with copper supply lines embedded in or running directly beneath the slab. Three decades later, those lines are starting to develop pinhole leaks, either from the inside out (water chemistry over time) or from the outside in (clay soil shifting and abrading the copper).
The clay soil specifically is the part of the equation that makes North Fulton different from, say, a coastal Georgia market. North Fulton clay is expansive — it swells when wet and contracts when dry, and that seasonal movement puts cyclical stress on anything embedded in the slab. After 30 years of swell-shrink cycles, even good copper develops fittings that fail and runs that abrade through.
Cold-side slab leaks are quieter and slower to show up than hot-side leaks. Hot-side leaks usually announce themselves with a warm floor and an obvious bump in the gas or electric bill (because your water heater is heating water that's flowing into the ground instead of to your tap). Cold-side leaks often only show up as a high water bill and the audible running-water sign.
How we diagnose without cracking your slab open
The phrase "slab leak detection" gets thrown around loosely. Here's what actual professional detection looks like, in the order we do it:
Step 1 — Isolation. We first confirm there is in fact a leak, and that it's on the supply side, not the drain side, and that it's under the slab rather than in a wall or ceiling. We do this with a meter test — close every fixture in the house, watch the water meter for movement, then close the main shutoff and watch again.
Step 2 — Acoustic listening. Pressurized water escaping a pipe makes a characteristic sound. We use a ground microphone to walk the slab and listen for the loudest point. On quiet houses with relatively new concrete, this alone gets us within a foot of the leak.
Step 3 — Thermal imaging. A hot-side leak heats the slab and the floor surface above it. A thermal camera makes that warm zone visible in seconds. For cold-side leaks we sometimes run a short hot-water flush through the cold supply (when plumbing layout permits) to create a temporary temperature differential we can image.
Step 4 — Electronic line tracing. Where layout is unclear, we trace the actual route of the supply line with an electronic transmitter and locator so we know exactly which line is leaking and exactly where it runs.
We do not jackhammer a slab open as a diagnostic step. By the time we open concrete, we know within inches where the leak is. That single discipline is what separates clean repairs from full-room demolition.
Repair options once we've pinpointed it
You generally have three options. We walk you through which fits your situation before any concrete gets touched.
Spot repair. Open a small section of slab directly over the leak, cut out the failed section of copper, splice in a new run, pressure-test, close up. Best for single isolated leaks in homes where the rest of the plumbing looks healthy. Lowest cost. Doesn't address future failures on the rest of the line.
Rerouting. Abandon the failed line in the slab, run a new line overhead through the wall cavity and attic to reach the same fixture. Avoids further slab demo. Best when the line geometry permits and the home has accessible attic and wall paths.
Epoxy pipe lining. Cure-in-place epoxy lining inserted into the existing pipe creates a new pipe within the old one. Best for homes with multiple developing leaks on the same line, or where rerouting isn't practical. Highest cost upfront, lowest disruption.
If we see multiple slab leaks developing on different lines, we have an honest conversation about whether a partial repipe or a full repipe makes more financial sense than chasing leaks one at a time. Whole-home repiping often pencils out better than three separate slab-spot-repairs over the course of two years.
A note on post-tension cable slabs (found in some commercial builds and a small number of newer residences): we do not cut or core a post-tensioned slab without confirming cable layout from the original plans. If you're unsure whether your slab is post-tensioned, mention it on the call and we'll bring a rebar/cable scanner.
Why Alpharetta sees more slab leaks than the national average
Three local factors compound. Building era — most slab-on-grade subdivisions here were built in a 13-year window that's now hitting the 30+ year mark, the typical onset window for copper pinhole leaks. Soil — North Fulton clay's expansive properties drive cyclical pipe stress. Water chemistry — Chattahoochee-sourced municipal water has a treatment profile that, while perfectly safe to drink, is moderately aggressive toward older copper.
Combine all three and you get a market where slab leaks are not unusual events; they're a predictable consequence of housing-stock age. Windward, parts of Webb Bridge, Brookwood, North Park, and pockets of Old Milton see them most. If your home is on a slab and was built 1985–1998, monitor your water bill monthly and treat any sudden jump as a possible slab leak until proven otherwise.
The Fulton County leak adjustment credit is available if you've already been billed for water that escaped a slab leak. We provide invoice documentation in the format the county requests.
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Frequently asked
How much does slab leak repair cost in Alpharetta?
Costs vary widely based on which repair option is appropriate. A single spot repair on an accessible leak typically runs significantly less than a reroute, which in turn runs less than epoxy lining or a partial repipe. We give a fixed price after pinpointing the leak and explaining options — we do not quote slab leak repair sight-unseen because the variables are too large.
Will my homeowners insurance cover this?
Policies generally cover the resulting water damage but not the cost of accessing and repairing the failed pipe itself. We provide itemized invoices that separate the access/repair work from the water damage remediation so your insurer has clean documentation. If your home still has polybutylene, also be aware that some carriers are non-renewing PB homes at policy anniversary.
How do I know it's a slab leak and not a different leak?
The three classic symptoms are a sudden unexplained water bill increase, a warm or hot spot on the floor, and audible running water when every fixture is closed. Diagnostic isolation (meter test with everything shut off) confirms whether it's a supply-side leak under the slab versus a drain leak versus a wall or ceiling leak.
Can I just patch a slab leak myself?
No — even setting aside that you'd need to break concrete to access the pipe, the harder problem is locating the leak precisely without professional acoustic and thermal equipment. Homeowners who attempt DIY slab leak repair typically end up demoing several square feet of floor before finding the leak, then still needing a plumber to do the actual pipe repair.
How long does the repair take?
Spot repairs are usually a same-day job — locate, open, repair, close — though concrete cures and floor finish restoration extend the visible timeline to a few days. Rerouting is one to two days. Epoxy lining is one to three days depending on linear footage.