HOME & FAMILY

Hidden Water Line Leaks

Hidden leaks on a pressurized water line cause a lot of damage before you know they exist. The first clue is often a large water bill. They are usually underground, or under the foundation. This page is about finding them, then the options for fixing them.

Just finding the leak yourself can save both time and money

These leaks range from easy to difficult to repair. Even if you do not do the repair yourself, just finding the leak before you hire someone else is still worth the time.

How to find those leaks

Finding leaks

Which pipes are yours, simple leaks to rule out before you hunt the big one, and how to tell a house leak from an underground leak or a slab leak.

In this video, a master plumber goes through the definitions of which pipes you are responsible for fixing and how to determine if there are leaks in your plumbing (both water and sewer) system. Later videos will show you ways that you can check for water leaks without calling a plumber.

Thanks to Roger Wakefield Plumbing Education for the YouTube video.

Watch on YouTube ↗

This video goes through 7 areas where you may have overlooked simple leaks. These leaks may not be causing the huge water bill, but they need to be eliminated so that you will be able to find that big, hidden leak.

Thanks to Any Hour Services - Electric, Plumbing, Heating & Air for the YouTube video.

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This video shows more ways to determine where you have a water leak in your house.

Thanks to PEX Universe for the YouTube video.

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This pair of videos shows you how to localize a slab leak and an underground leak.

Thanks to Trifco Studio and Twin Home Experts for the YouTube videos.

Underground leak ↗ Slab leak ↗

Grandpa TJ’s cautionary tale

We found an under-slab hot-water leak because a section of floor was hot to step on, and the water meter confirmed it. There was no moisture around the hot spot, so mold and water damage were not factors. A company we thought was leak detection rushed out, skipped a moisture test, and set up fans to dry a leak that was not wet. If moisture had been on the slab or walls, fans would have been right. They were not, and they should have said so. I told them to pack up their equipment and leave.

Do not get pressured into service you do not need. Ask a lot of questions.

After that false start, we called a leak-detection service that used high-tech gear to map the leaking pipe right through the slab without any digging. It turned out that the leaking pipe ran straight from the water heater to the bathroom. That made the plumber's job easy.

Slab leaks

What causes slab leaks, including what matters when you talk to insurance, what to know before you open a wall or floor, and pro repairs that expose the pipe or tunnel under the foundation.

This video by a master plumber goes over many of the causes of slab leaks that can be important when it comes time to speak with your homeowner's insurance company.

Thanks to Roger Wakefield Plumbing Education for the YouTube video.

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This video goes over important things to know about slab leaks – especially before you start tearing open walls or floors.

Thanks to CRC Plumbing for the YouTube video.

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This video shows how an under-slab leak is found and exposed. The repair process would be the same as shown in other videos here.

Thanks to Plumbing Kings LLC for the YouTube video.

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This video shows another through-the-slab leak being repaired by a plumbing company.

Grandpa TJ: This video is what I call a “video diary” of running commentary rather than an actual how-to video but it shows some of what happens during through-the-slab repairs.

Thanks to In-House Plumbing Company for the YouTube video.

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This video shows how this plumbing company actually has to tunnel under the foundation to find and repair the leak – you can bet it was expensive! The nice thing is that they also found both a second leak and a potential leak and made repairs to both of those at the same time.

Thanks to Roger Wakefield Plumbing Education for the YouTube video.

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The attic bypass option – Grandpa TJ’s cautionary tale (cont.)

After finding and mapping out the leaking pipe, we consulted the plumber about what could be done. Although we could dig through the slab and repair the leak, he recommended that we bypass the whole under-slab section by going through the attic and downwards into the bathroom, instead of jackhammering open the slab to fix a 40-year-old pipe that was only likely to leak again. An elegant solution to a big problem.

Bypassing slab leaks

Ways around a slab leak instead of opening the slab: overhead PEX, an exterior copper run, another PEX bypass, and a long copper bypass with the soldering work.

This video shows how overhead PEX pipe is used to bypass a leaking copper pipe under the slab.

Thanks to Cliff Morgan for the YouTube video.

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These videos show how an exterior copper bypass is done to eliminate a leaking copper pipe under the slab.

Thanks to Twin Home Experts for the YouTube videos.

Part 1 ↗ Part 2 ↗

This video shows another PEX bypass being done.

Thanks to Southern Stories for the YouTube video.

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This long video shows a copper bypass being done along with all of the prep work and even a short tutorial on soldering (sweating) copper joints.

Thanks to Joe's Garage for the YouTube video.

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Leaks in walls or ceilings

Leaks behind drywall or in a ceiling. One had been running behind a toilet wall long enough to grow mold; a steel nail was touching the copper, not puncturing it. Another was a longer mystery leak.

This video shows a leak that had been running behind the drywall behind a toilet for quite a while creating damage and mold. Spoiler: they discovered that a steel nail caused the leak – not because it punctured the pipe – but it was just touching the copper and that caused it to fail…

Thanks to Wesley Fazekas for the YouTube video.

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This kind of long but fun video shows a mystery leak that took some real detective work to find.

Thanks to Matt Risinger for the YouTube video.

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Before you dig

Have local utilities mark underground services before you dig. It is often free, and in many places the phone number is 811. Do not turn a water leak into a power outage, a gas leak, or a broken internet or sewer line.

The video located here has a good overview of what kinds of underground services you need to be aware of before digging.

Thanks to OCC Studios for the YouTube video.

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Underground leaks in the yard

Finding and fixing a leak in the yard: a plastic main between the meter and the house, a pinhole in a copper supply, a rusted PVC-to-copper union, and a well-pump-to-house leak found with an air compressor.

This video shows you how to find and repair an underground plastic water main between the meter and the house. NOTE: the underground utilities locator marks were done in this video.

Thanks to River Life WV for the YouTube video.

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This video shows how a pinhole leak in a copper water supply line is solved with just a fitting.

Thanks to Video MyGoodness for the YouTube video.

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This video shows the repair of a rusted joint in a PVC to copper water main union.

Thanks to Pete B: East Texas Homesteading for the YouTube video.

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This video shows how a leak between a water well pump and a house was located using an air compressor to aid in finding the leak.

Thanks to PSI4H2ODr for the YouTube video.

Watch on YouTube ↗

Where to next?

Back: Water Line Leaks Start over: Water Leaks at Home

Need help with your situation?

Email Grandpa TJ for free, unbiased advice, or join the Inner Circle when you need a real conversation with a real person.

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