Tile Warm Entire Length of Hot Water Line. Slab Leak

[AZTom1]

I've lived in this house for almost 20 years and recently noticed some warm spots on the tile.

My first thought was a slab leak. (Had a cold water side slab leak rerouted two years ago.) As I investigated, I discovered that the tile is warm for the entire length of the hot water line, approx 45-50 feet. No recirc. pump. It's also warm first thing in the morning, before any showers, etc.

I've checked the meter a bunch of times and it doesn't seem to be moving at all. Just took 2 pics of the meter an hour apart and they're identical. (With our cold slab leak the little wheel on the meter was spinning when all fixtures were turned off.) I've turned off the hot water at the water heater for 5 minutes and turned it back on to see if I would hear water running back into the pipes. No running, just the smallest fft sound when I opened the valve.

I can't say for sure that this hasn't been going on for a long time. I'm almost always in shoes or flip flops.

Any thoughts? This is a 50 y.o. ranch house in the Phoenix area, if that matters.

 

[Jadnashua]

If the meter isn't running, it does not appear that you're losing water. Depending on how the lines are run, some convection might occur, but I'd be surprised if it could maintain that overnight enough without flow for you to be able to feel it in the morning prior to running any hot.

I guess that a very slow leak could still be occurring. Not sure if that would be enough to keep the line hot. I'd note the meter reading when I went to bed or after the last water use, and then again in the morning, or as long of a period as you can. Can't think of anything else other than a leak that could cause that strip of heating, but you could turn the WH off overnight and shut the inlet to it. That should at least prevent any flow, but may not stop any convection. It's possible, that if you have a heat trap on the WH, that it has failed. That would be easy to remedy. One way to create a heat trap is with a dip in the outlet pipe of the WH's hot line rather than a heat trap that goes on the top of it. That should not fail over time!

 

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[AZTom1]

If the meter isn't running, it does not appear that you're losing water. Depending on how the lines are run, some convection might occur, but I'd be surprised if it could maintain that overnight enough without flow for you to be able to feel it in the morning prior to running any hot.

I guess that a very slow leak could still be occurring. Not sure if that would be enough to keep the line hot. I'd note the meter reading when I went to bed or after the last water use, and then again in the morning, or as long of a period as you can. Can't think of anything else other than a leak that could cause that strip of heating, but you could turn the WH off overnight and shut the inlet to it. That should at least prevent any flow, but may not stop any convection. It's possible, that if you have a heat trap on the WH, that it has failed. That would be easy to remedy. One way to create a heat trap is with a dip in the outlet pipe of the WH's hot line rather than a heat trap that goes on the top of it. That should not fail over time!

Thank you!

 

[Steven Xu]

I've lived in this house for almost 20 years and recently noticed some warm spots on the tile.

My first thought was a slab leak. (Had a cold water side slab leak rerouted two years ago.) As I investigated, I discovered that the tile is warm for the entire length of the hot water line, approx 45-50 feet. No recirc. pump. It's also warm first thing in the morning, before any showers, etc.

I've checked the meter a bunch of times and it doesn't seem to be moving at all. Just took 2 pics of the meter an hour apart and they're identical. (With our cold slab leak the little wheel on the meter was spinning when all fixtures were turned off.) I've turned off the hot water at the water heater for 5 minutes and turned it back on to see if I would hear water running back into the pipes. No running, just the smallest fft sound when I opened the valve.

I can't say for sure that this hasn't been going on for a long time. I'm almost always in shoes or flip flops.

Any thoughts? This is a 50 y.o. ranch house in the Phoenix area, if that matters.

hey Tom, did you ever figure out what was causing this? I’ve noticed something identical in our house in Austin. Warm (+5 degrees vs surrounding tile) tile across the length of what may be a hot water pipe. No leak per our water meter.

 

[AZTom1]

It was indeed a slab leak. Had a leak finder guy come out and he diagnosed it in about two minutes. It was slow enough that the meter didn't move, but enough to really heat up the floor. When I had the cold side leak fixed a couple years ago the plumber ran an extra length of PEX through the attic when he did the reroute, figuring it was just a matter of time until the hot side started leaking. Didn't connect it to anything, just ran it between the manifolds. Because of that, this reroute was a little less expensive to fix. Good luck!

 

[Jeff H Young]

you don't look at the numbers on the meter you look at the little wheel that spins. the clue was you turned off water at the heater for 5 minutes and heard pfst noise when re opening the hot floor a giveaway as well