Is There Water Running Under Your Floor?

A slab leak hides in the one place you can’t inspect: inside or beneath the concrete your house sits on. By the time it’s obvious, water has often been running for weeks. These are the signs homeowners notice first:

  • A warm or hot spot on the floor, often the clearest sign of a hot-water slab leak
  • A water bill that jumped with no change in how you use water
  • The sound of running water when every faucet in the house is off
  • Your water meter creeping forward while nothing inside is running
  • Cracks appearing in the slab, tile, or flooring that weren’t there before
  • A damp, musty smell or moisture wicking up baseboards and carpet edges
  • Low water pressure that faded gradually over weeks, not overnight

Sacramento’s expansive clay soil makes slab leaks especially common here. It swells in the wet months and shrinks in the dry ones, and that constant movement stresses the copper lines run in or under the foundation. Homes built before the 1990s with copper under the slab sit in the highest-risk group. The longer a slab leak runs, the more it erodes the soil supporting your foundation, so finding it early is what keeps a plumbing problem from becoming a structural one.

Not Every Slab Leak Is the Same

Where the leak is and which line failed changes how it shows up and how we find it. These are the three we see most often under Sacramento homes.

Hot-Side Pressure Leaks

The most common slab leak and usually the easiest to locate. A pressurized hot-water line under the slab develops a pinhole or crack, and the escaping hot water warms the concrete above it. That's the "warm spot on the floor" homeowners describe, sometimes with a jump in the gas or electric bill because the water heater keeps reheating water that's draining into the ground. We find these with thermal imaging and acoustic listening.

Cold-Side Pressure Leaks

Trickier, because there's no warm spot to give it away. A cold-water line under the slab leaks silently, so the tells are a higher water bill, the sound of running water with everything shut off, and a meter that won't sit still. These take acoustic equipment and pressure testing to isolate, since the surface may look and feel completely normal.

Drain-Line Slab Leaks

Not a pressurized line but a waste or drain pipe under the slab that has cracked or separated. Signs lean toward a sewage or musty odor, damp flooring, or water surfacing near the perimeter of the house. These are harder to pin down from pressure alone, so we often combine camera inspection with acoustic and moisture readings to trace the break.

From First Suspicion to a Located Leak

No guesswork, no open-ended timelines. Here’s exactly how we track down a slab leak.

Confirm the Leak Is Real

We check your meter, test static pressure, and inspect visible plumbing to confirm you actually have a slab leak and narrow down whether it's a hot line, a cold line, or a drain. This rules out simpler causes before anyone touches the floor.
Step 1

Pinpoint It Without Digging

Using acoustic, thermal, and electronic equipment, we locate the leak through the concrete, with no exploratory holes. You watch the process with us and see what we're finding in real time.
Step 2

Explain What We Found

Once we've pinpointed the source, we walk you through exactly what's leaking and where, in plain language, and lay out your options: a spot repair through a single access point or, in some cases, rerouting the line above the slab if that's the more cost-effective long-term fix.
Step 3

Repair, If You Want Us To

Because we're a full plumbing company, the same crew can carry out the repair once you approve it, so you're not left calling a second contractor with a diagnosis in hand. Detection and repair, one team.
Step 4

Document Everything

You get clear documentation of the leak location and cause, useful for your own records and exactly what a homeowner's insurance adjuster needs if you file a claim for the water damage.
Step 5

The Tools That See Through Solid Concrete

Finding a leak under a slab isn’t about a bigger wrench. It’s about equipment that can locate water through four inches of concrete before we ever pick up a saw. Here’s what we bring to a slab leak.

Acoustic Listening Devices

Pressurized water escaping through a pinhole creates a distinct sound frequency. Our acoustic sensors amplify that sound through concrete and soil, letting us hear exactly where the water is escaping under the slab, often to within a few inches, so the floor gets opened in one precise spot instead of guesswork.

Thermal Imaging Cameras

A hot-water slab leak warms the concrete above it in a pattern the eye can't see but infrared can. We map that heat signature to narrow the leak location before any cutting begins, which is what makes finding a hot-side leak fast and non-destructive.

Electronic Line Tracing

Before we detect, we map. We trace the actual path of the water lines under your slab electronically, so we know exactly where the pipe runs and where to focus. Combined with pressure testing, this isolates the leak to a specific section rather than the whole line.

Moisture Meters

Where a slab leak surfaces, it saturates flooring, subflooring, and baseboards along the way. We use pin and pinless moisture meters to read those saturation levels and trace the water back to its source instead of chasing the spot where the damage happened to appear.

Why Sacramento Homeowners Call Us to Find Their Slab Leaks

Precision Before We Cut

We never break into a slab until our equipment has confirmed the exact leak location. The whole point is precision: one small access point, not a series of exploratory holes across your floor hoping to get lucky.

Detection and Repair, One Team

Most companies find the leak and hand you a phone number to call someone else. We're a full plumbing company, so if you want the leak fixed, the same crew that pinpointed it can repair it. One team, one point of accountability.

Flat-Rate, Approved in Advance

Detection is quoted as a flat rate, so you know the cost of finding the leak before we start. If you choose to move forward with a repair, that's quoted separately and approved by you before any work begins. No hourly meter running.

Documentation Your Adjuster Needs

Many homeowner policies cover sudden water damage from a slab leak. We provide detailed documentation of the leak location and cause, exactly the paperwork your insurance adjuster needs to process a claim.

Financing & Referral Program

Flexible Payment Options

For larger projects, financing is available through Wisetack. 
Quick application with a soft credit pull.
Learn More

Our Referral Program

Refer a friend or neighbor to 5-Star Plumbing and earn cash rewards 
when they complete their first service with us.
Refer Now

Flexible Payment Options

For larger projects, financing is available through Wisetack. 
Quick application with a soft credit pull.
Learn More

Slab Leak Questions, Straight Answers

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