Location
Gilbert, AZ
Service
Slab Leak Detection
Issue
Warm floor, $80 water bill spike, original 1987 copper
Outcome
Leak confirmed and located, line rerouted through attic

We got the call from a homeowner in Gilbert, off Warner Road in one of the older established neighborhoods out there. 1987 build. She'd noticed something strange in the hallway — a section of tile that felt warm underfoot, noticeably warmer than the surrounding floor. She'd also just opened her SRP bill and it was about $80 higher than any month she could remember. She wasn't sure the two things were connected. They were.

Warm spot on the floor plus an unexplained spike in the water bill is one of the clearest presentations of a slab leak we see. We told her that on the phone and scheduled the detection visit.

The Detection

Slab leak detection is done with electronic listening equipment — we use acoustic amplification tools that let us hear water movement through the concrete. The process is methodical. We isolate the water lines, pressurize them, and work through the floor systematically, listening for the sound signature of a pressurized leak. Water moving through a pinhole in copper under pressure makes a distinctive sound. With good equipment and a quiet house, you can locate a leak within a few inches without cutting into anything.

We confirmed an active leak in the hot water supply line. That matched the warm spot — the leaking hot water was migrating through the concrete and warming the tile above it. We located it precisely to a section of the hallway about four feet from the master bedroom doorway. Knowing exactly where the leak is before you start any repair work matters. Every unnecessary square foot of jackhammering into a slab is time, money, and disruption. Precise location keeps the scope of work tight.

What We Were Working With

This is a 1987 home with original copper throughout. That's not automatically a problem — copper is a good pipe material and plenty of it is still performing fine decades later. But there are two things that work against copper over time in the Phoenix area, and both of them were at play here.

First is the soil. The expansive clay soils common in the East Valley shift seasonally as they wet and dry, and that movement creates stress on pipes embedded in the slab. Over 30-plus years, that repeated micro-movement causes work-hardening and eventual pinhole failure at stress points. Second is water chemistry. The hard, slightly aggressive water in this part of Arizona accelerates pitting corrosion on the interior of copper pipes over time. The combination of soil movement stress and internal corrosion is why pipes in 1980s homes fail — and why when they fail once, they tend to fail again.

We told the homeowner that directly. This wasn't the first pinhole this system had developed, even if she hadn't seen the signs before, and it wouldn't be the last. The active leak we located was the presenting problem, but the underlying condition — aging copper under a concrete slab in Arizona soil — wasn't going away with a spot repair.

The Three Options

We gave her three options. We laid them out clearly, explained the tradeoffs of each, and told her what we'd recommend and why. These are the same three options we present on every slab leak job where the plumbing is original and aging.

Option 1
Spot Repair — Access and Patch the Current Leak

We jackhammer into the slab at the leak location, expose the pipe, cut out the failed section, and repair it with new copper and fittings. We patch the concrete and it's done. Cost range for a job like this: roughly $800–$1,400 depending on depth, access, and flooring restoration. This fixes today's problem. It does nothing about tomorrow's problem — the rest of the aging copper that's still under the slab. On a 1987 home, spot repairs tend to be a temporary solution. Many homeowners do one, then do another 18 months later when the next pinhole appears, and eventually they've spent more than a reroute or repipe would have cost and they've still got the original pipe under the slab.

Option 2
Reroute the Affected Line Through the Attic

Instead of repairing the failed line in place, we abandon it entirely and run a new line — PEX or copper — through the attic space and back down to the fixtures it serves. The old line stays in the slab, decommissioned. The new line is above the slab, accessible, and not subject to the soil movement and corrosion conditions that failed the original. Cost range for a single-line reroute: roughly $1,200–$2,000 depending on line length and the number of fixtures it serves. This permanently addresses the affected line. It doesn't address the other original copper lines still under the slab — but if only one zone is presenting problems, it's a sensible middle-ground solution. Good value for its scope.

Option 3
Full Repipe with PEX

We repipe the entire house — every supply line, hot and cold — with cross-linked polyethylene (PEX) tubing run through the walls and attic, eliminating all original copper from service. This is the complete solution. No more slab-embedded copper anywhere in the house. PEX is flexible, resistant to the pinhole corrosion that affects copper in this environment, and the attic routing makes future access and repairs straightforward. Cost range for a full repipe on a 1987 single-story home of this size: roughly $7,500–$10,500. It's the largest upfront number, but it's also the last plumbing decision you make on supply lines for the foreseeable future. No more slab leaks. No more detection calls. No wondering what's next.

What She Chose — and Why It Made Sense

She went with Option 2 — the line reroute. We think it was the right call for her situation.

The reasoning: this was the first slab leak symptom she'd had in the 11 years she'd owned the home. The affected line served the hallway bathroom and part of the master — not the whole house. Her budget didn't make a full repipe comfortable right now, and she wasn't planning to sell in the near term, so the long game of getting ahead of every possible future failure wasn't a financial priority. The spot repair felt like renting a solution. The reroute permanently removed the problem zone from the equation at a cost that fit her circumstances.

We ran new PEX from the water heater, up through the attic, and back down to the hallway bath and master. Decommissioned the original hot water line in the slab. No jackhammering. The hallway tile stayed intact. She was back to full hot water the same day.

We also told her: watch the other bathrooms. If she sees another warm spot, another bill spike, or hears running water when everything's off, call us. The cold water lines and the lines serving the kitchen are still original copper, still under the slab. They may be fine for another decade. They may not. She knows what the signs look like now, and she knows she's got a decision to make about a full repipe somewhere on her horizon.

A Note on Detection Before You Dig

We want to say this clearly because not every company approaches slab leak jobs this way: proper electronic detection before any jackhammering is not optional. We've been called in after other contractors opened up a slab based on a rough guess — "it's probably around here" — and the leak was 18 inches away from where they cut. That's 18 inches of unnecessary concrete damage, tile loss, and labor the homeowner paid for. Precise detection is not a premium add-on. It's how this job is supposed to be done.

For more on how we approach slab leak work, see our slab leak detection page. If you're weighing a full repipe against repeated repairs on an older home, our whole-home repiping page lays out how we think about that decision.

Takeaway for Homeowners

If you have a home built before 1995 with original copper plumbing and you notice a warm spot on the floor, hear water running when all fixtures are off, or see an unexplained jump in your water bill — those are the warning signs of a slab leak and they warrant a detection call, not a wait-and-see approach. The longer a slab leak runs, the more moisture saturates the subfloor and foundation. Electronic detection is precise and non-destructive. Get the leak located before anyone starts cutting. And on any home with aging in-slab copper, ask for all three options — spot repair, reroute, full repipe — and understand the tradeoffs before you decide. The cheapest option today isn't always the cheapest option over the next five years.