Slab leak. That was the diagnosis from the specialized slab leak detecting company. Fortunately, the customer called me to get a second opinion.

Slab Leak Detection Specialists Can Overlook Less Costly Leak Causes

Slab Leak Detection Equipment = Just a Tool

Sure, I take advantage of all the latest diagnostic equipment on the market too. But they’re just tools. They don’t tell the whole story any more than a doctor’s stethoscope. They give you clues, symptoms, but they’re not a diagnosis.

I look for clues to pinpoint the true source of the problem. That’s part of what I love about being a plumber. There’s clues everywhere. A mystery to be solved.

Specialists Prone to Overlooking Other Sources of Leaks

After more than 30 years in the general plumbing field, I still run across challenging mysteries. Those years of experience give me an edge over other less-experienced plumbers and those who “specialize” in leak detection.

In this case, the leak detection company used acoustic-type sensing technology. The equipment detected the sound of water flowing. The technician interpreted that sound as a slab leak. That’s what slab leak technicians are trained to listen for and focus on. So that was their diagnosis.

A Holistic Approach to Troubleshooting Water Leaks

I’m a general, all-round plumber with decades of experience solving all types of plumbing issues. I started out learning the plumbing trade as a kid in my dad’s plumbing business. That was long before high-tech diagnostic tools. Back in those days, we had to look for clues all around. Not wear blinders or jump to conclusions. That old-school experience taught me a lot. I’ve learned to look at the bigger picture.

In other words, I’m more holistic in my approach to identifying the true source of a plumbing problem.

Before bringing out specialized high-tech equipment designed to detect a slab leak, for example, I first eliminate other possibilities. And those possibilities are not as stressful or costly to fix as a slab leak.

Save Money and Gain Knowledge

Knowledge is power. So I’m going to share with you some of the ways to arm yourself with knowledge I’ve gained throughout the years. Follow along and you’ll be able to troubleshoot a water leak and save money.

Plumbers, like most professionals, charge by the hour. If you can successfully troubleshoot the source of the water leak yourself, you’ll save yourself money in two ways:

  • #1. You’ll show the plumber you’re knowledgeable. And knowledgeable people are less likely to be hoodwinked and overcharged.
  • #2. Less time for the plumber means more savings for you.

First Eliminate Other Less-Costly Water Leak Sources

Before believing the problem is a slab leak, first eliminate other less-costly potential sources of the problem.

1. Always Check the Water Meter

First check your water meter when all the water is off in the building and see if the meter is showing a flow.

2. Check the T&P Valve on the Water Heater

My experience told me to first check the T&P valve (Temperature & Pressure relief valve) on the water heater. And in this particular case, my experience paid off. The T&P valve, was indeed, the source of the problem.

Temperature and Pressure valves are located at the top of a Bradford brand water heater.
This is a Temperature & Pressure valve on a Bradford Water Heater. It’s at the top. Other water heater brands may have T&P valves at the side.

In this case, the T&P valve was leaking into a drain and directing water into another location. As water ran down the drain from the leaking T&P valve, the slab leak detection sensors picked up the sound. The technician interpreted that sound as a slab leak.

I understand the error. Slab leak technicians are focused on their equipment’s output. And the output was audible. Therefore, in the technician’s “world view” as a slab leak specialist, it was a slab leak.

But it could have been a costly and stressful error for the homeowner if she had she gone with that specialist’s diagnosis.

3. Inspect the Toilet’s Seal

If the T&P valve isn’t leaking, here’s what to look for next. Inspect the seal of every toilet in your home or building. A toilet seal can leak and the water can travel down the trowel grooves for several feet under the tile and reappear far from the toilet. That leak can also simulate the sound of a slab leak.

4. Identify the Leak as Hot or Cold

You can find out if the leak is on the hot or cold side by turning off the hot water to the hot water heater. Wait a few minutes, then turn it back on. If it’s a hot leak, you’ll hear the water flowing when you turn the hot water heater back on. The same is true for the cold side when the hot valve is off.

5. If a Water Pipe is Leaking …

The leak may be at the top of the slab, inside a wall, not in the slab itself. That, too, could acoustically simulate a slab leak.

Other Clues Require a Plumbing Professional

There are other tips to troubleshooting a leak. But they require the right tools and equipment. Just as importantly, they require a professional plumber with a background of old-school troubleshooting experience who knows how to use the equipment.

If it IS a Slab Leak …

If it turns out to be a a pipe leak underneath the slab, don’t be surprised if you have another one. In some older homes, the copper in pipe was not high quality. Even in newer buildings, earth shifting can cause pipes to crack.

After a second leak, in most cases I generally recommend a complete re-pipe. Put your money into a permanent fix.


I hope you use this information to arm yourself against dishonest plumbers who overcharge. And against those who are just too inexperienced or too “specialized” to know any better.

Specialists in all professions have their place. But you’ll save money if you use the information above to first try to troubleshoot to find the source of a leak yourself.

Then, if you find the source of the leak you’ll save a plumber’s time and your money.

If you can’t find the source of the leak yourself, still call a general all-round experienced plumber first. Hopefully, you’ll call me.

I want to earn your trust here by sharing what I know that could help you save money. And by the five-star customer satisfaction ratings my business consistently receives. (Read some of those ratings here.) You’ll also find out more about my business philosophy and reasons to choose me here.

Perhaps a slab leak detection specialist is somewhat like a surgeon. After all, surgeons are trained to look for problems that require surgery. That’s just their “world view”. If you first go to a specialist like a surgeon before going to your general practitioner who looks at your symptoms, you’re likely to end up having surgery.

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