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How Does a Plumber Check for a Slab Leak?

Benjamin Franklin Plumbing Tech, Trevor, with two homeowners at their house in Melbourne, FL How does a plumber check for a slab leak?How does a plumber check for a slab leak?

Slab leaks are sneaky water leaks that happen under your concrete foundation. They’re especially tricky because you often won’t notice them until they’ve caused severe damage. And if you’re in Melbourne, FL, you’ll want to pay extra attention since our hard water, corrosion issues, and shifting soil make our homes particularly vulnerable.

Water quietly leaking under your floor is bad enough, but under your foundation? It can weaken your entire house’s structure. But don’t worry; I’ll walk you through how plumbers find these hidden troublemakers.

What is a Slab Leak?

You’ve got water pipes running under your home’s concrete foundation. When one of these pipes develops a leak, that’s what we call a slab leak. These typically appear in copper water lines, and they’re tricky to spot because they’re buried under concrete!

Here’s something interesting: slab leaks are different from those regular pinhole leaks you might find in your visible plumbing. They can happen in two places: the pressure side (where water comes into your home) or the drainage side (where it leaves). Pressure-side leaks are actually easier to catch because you’ll notice changes in your water pressure and usage. Drainage-side leaks? Those are the real ninjas; they can hide for ages without showing obvious signs.

The Consequences of a Slab Leak

Trust me, you don’t want to find out the hard way.

We’re talking about:

  • Your floors, walls, and cabinets getting water damage
  • Mold and mildew making themselves at home (and nobody wants that!)
  • Termites throwing a party (they love damp spaces)
  • Your foundation gradually weakening

This is exactly why getting regular professional inspections is so important. A good plumber can catch these issues early before they turn into a nightmare.

How Long Can a Slab Leak Go Undetected?

Would you believe these sneaky leaks can go unnoticed for weeks, months, or even years? It’s wild, right? The problem is that the longer they stay hidden under that concrete, the more damage they cause. We’re talking about mold spreading everywhere, foundations shifting, and thousands of gallons of water wasted.

It’s just an unfortunate reality that, while sometimes it’s easy to find out exactly where a pipe is leaking, that is not the case for slab leaks.

What Causes a Slab Leak?

Sometimes, it’s just poor installation; maybe those pipes got damaged during construction or weren’t put in quite right. Or think about this: pipes naturally expand and contract with temperature changes. They’ll eventually wear down if they’re rubbing against concrete, gravel, or other pipes. And don’t get me started on corrosion; our soil conditions and water quality can be harsh on pipes, especially copper ones.

What Does a Slab Leak Look Like?

Your foundation is always moving slightly (yes, really!), and this movement can put pressure on pipes until they crack. While you might not see the movement itself, you might notice cracks in your walls, mysterious damp spots, or even warm areas on your floor. These are all red flags!

Signs You May Have a Slab Leak in Your Home

  • Your water bill suddenly skyrockets for no reason
  • You hear the sound of running water when everything’s turned off
  • Finding damp or mildew under your carpets
  • Your water meter’s moving when all water is off
  • Random puddles outside your house
  • Unusually low water pressure
  • Cracks showing up on walls or baseboards
  • Warm or damp spots on your floors
  • Musty smells that scream “mold!”

If you notice even one of these signs, it’s time to get it checked out.

How Does a Plumber Check for a Slab Leak?

Plumbers use specialized tools and techniques for accurate slab leak detection.

Here’s how they do it:

  1. Visual Inspection: First, we check your home for signs of water damage, mold, or unusual dampness.
  2. Acoustic Listening Devices: Plumbers use high-tech listening equipment to detect the sound of water leaking beneath concrete. These devices amplify the noise of escaping water, allowing for pinpoint accuracy.
  3. Thermal Imaging: Infrared cameras detect temperature variations in the foundation, revealing areas where hot or cold water is leaking.
  4. Pressure Testing: Plumbers can determine if and where a leak is present by isolating sections of your plumbing system and applying controlled pressure.
  5. Electronic Leak Detection: Specialized equipment uses electromagnetic signals or conductive fluids to trace water flow, helping plumbers find even the smallest leaks.

Now What?

Once a professional plumber confirms you’ve got a slab leak, they’ll talk you through your options. Sometimes, they can repair the damaged section of the pipe. But if your plumbing system’s getting up there in age or the leak’s in a really tough spot, you might need to look at bigger solutions, like rerouting your pipes with modern PEX piping.


Do you have a slab leak? Don’t sit on it! Every day you wait is another day for that leak to cause more damage.

If you’re in Melbourne, FL, give Benjamin Franklin Plumbing a call. Our punctual plumbers use all the latest tech to detect and repair leaks with minimal disruption to your home.

Remember: protecting your foundation, saving on water bills, and stopping mold before it spreads starts with making that call today!