Finding Small Hidden Leak on Hot Potable Water Supply Side

[DW85745]

I've isolated the Leak to the Down Stream side after the Hot Water Tank.
The Connections from the Hot Water Tank to the Wall are OK.
Anyone have any ideas for:
1) How I isolate the lines from inside the wall to each hot water faucet for leak testing, and
2) Once the problem line is identified, find the approximate location of the leak?

This house is on pier and beam s0 I can check a small portion of some of the lines under the house for any visible evidence of water -- work in progress.
However most of the lines are hidden and buried below grade, with about
a two foot thick concrete floor on top (think of a basement floor with just a 19 inch crawl space between the top of the basement floor and the bottom of the floor beams (joists)).

There does appear to be some sort of manifold assembly for pipe routing (no valves) in the crawl space area below where approximately the hot water tank is located above in the living space.

Any other approaches (including a workaround) appreciated.

 

[WorthFlorida]

If there is no evidence of dampness or water stains the leak is probably below the slab. If there is a manifold of some kind and there are shut off valves, you'd be in luck. If your hot water lines are daisy chained to each fixture, there will be alot of wall opening. There are companies that can find leaks and far more accurate than opening up walls. google "water leak detection tucson, az".

 

[Sponsor]

 

[DW85745]

WorthFlorida thanks for responding.

Had check out -- web id only - our local leak detection companies prior to posting.
My biggest concern is fact the lines are buried maybe a foot below the approx. two feet thick concrete slab.
AFAIK -- I'm sure I'm dated because of my age - is that my best alternatives may be temperature differential (Laser Temperature Sensor
or Thermocouple) or the use of a moisture meter. I doubt -- hopefully someone can onnfirm -- as to whether these listening devices
could evaluate a leak through that thick of concrete. I also am aware of using a low electric voltage with detector will determine line routing
but again will it pick up a signal through that much concrete.

 

[Mliu]

How do you know your concrete slab is 2 feet thick? That seems highly unlikely (unless your home was built upon a former atomic bomb shelter). I'm betting that you're seeing the 2 foot deep grade beam that makes up the perimeter of your slab. Within the perimeter, the slab is probably only 4 to 6 inches thick.

 

[DW85745]

Trust me it is two feet. My father built this home as an all solar home and there was a two foot thick layer of washed river rock as a heat sink,
While redoing a bathroom several years back I found rattlesnakes. They would slither into the rock bed and unknown how many there were.
So, I had a very loose mixture of concrete pumped under the entire house to fill the rock voids. Solved the rattlesnake problem, but created one thick concrete slab. FWIW my only other option was to try an remove the rock, which my estimate was over a year trying to bucket out -- one five gallon bucket at a time -- all that rock through a small opening in the kitchen pantry floor and I didn't particularly want to run into rattlesnakes doing it!!

 

[DW85745]

Right now I'm leaning toward just forgetting any leak detection and just either having a liner put into the hot water copper lines or cutting
the lines and going with a PEX reroute.
I got involved back in the late 1970's with SSES and relining large municipal sewer lines, but don't know much about doing small potable
water lines. Per web, appears they use some type of epoxy. Biggest question in my mind is whether the epoxy will break down and/or unknowingly leak chemicals into the potable water. Really kinda the same issue with the PEX since it is plastic. While PEX been around for
a few years, really does NOT have a long term history like copper.

 

[Reach4]

Maybe you could crank up the water heater. Use no hot water overnight. Then on a cool morning, use a FLIR camera to find the warmer area. The path of hot should be warmer, up to the leak. The leaking hot water might show a warm area too.

How did you know you have a leak?

 

[Mliu]

Trust me it is two feet. My father built this home as an all solar home and there was a two foot thick layer of washed river rock as a heat sink. ... So, I had a very loose mixture of concrete pumped under the entire house to fill the rock voids.

Are you sure the water pipes are buried under the 2 feet of river rock? If they ran through the rock bed, then they are now encased in concrete.

In any case, if your pipes are within or under your 2' slab and they are leaking, running new lines is probably the better way to go.

PEX has been around a lot longer than just a few years.

 

[DW85745]

---------
Reach4:
-----------
Well I found the general area of the leak. and MAYBE the specific pipe.
Below the water heater is the manifold and the concrete appears damp (different color than the all white floor).
The copper pipes were put into a protective sleeve prior to them being installed -- thank my dad for that one -- and in playing
with an opening in that covering between the concrete and the floor joists I found water
between the pipe and the sleeve. Not sure where that pipe goes
and if any branching off of it -- hopefully Not.

How id you know you have a leak.

Just kinda lucky I guess. Water bill was about $3.00 higher than normal and just out of curiosity thought I'd compare the meter reading to
the just received bill. From there just standard troubleshootiing to isolate piping. When the house was constructed my dad put a set of
valves near entry to the house which isolated the house water, outside water, and irrigation water. So ID house water was an easy go.
Next check toilets -- blues pills -- and no flapper leaks. Next tried shutting off inlet value to water heater and that ID the problem was downstream. Sadly, no valve on the outlet of water heater -- will put one in next time I replace it. SO just capped the line exiting the
heater and again no meter dial movement indicated a downstream issue. So just got back from crawling under the house to the various
hot water locations points -- entry and exit from concrete, and as per above was able ti ID the general area of the problem.

-------
mliu
-------

Are you sure the water pipes are buried under the 2 feet of river rock?

YES

running new lines is probably the better way to go.

Leaning in that direction. Just debating whether it might be worthwhile to use a powered chipping hammer and see if I can't
clear an area around the manifold piping and hope for the best. Don't want to inadvertently hit any line, but most likely the lines
go straight down before they bend -- but may have a radius (slow curve) as they make there way from the manifold to under the rock. Naturally, the pipe was installed prior to the rock.

PEX has been around a lot longer than just a few years.

Guess everything is relative. For me a few years is 25 or 30.

=============================
QUESTION:

Any suggestions as best / easiest way to ID whether the particular line I believe is the bad boy, is in fact it.
One approach I was considering was to cut the line near the manifold and see if I could bend it -- without kinking -
to see I could get access to its opening to put a plug in. If not, cut out a small section of line. Then remove the angle stop (compression
fitting) in the bathroom where I think the line runs. Lastly, plug the line at the manifold and then pressure test the line
using either a compressor or nitrogen and see if I have a leak.

The key here, is if I guess wrong I've done a lot of extra work for nothing. So any other alternative appreciated.

BTW how does one quote someone else's comments. I've been doing it using HTML markup code for quotes, but most forums have a quote button which I could not find.

 

[DW85745]

Just thought of what may be an easier way -- but still locking for alternatives.
1) Cut the suspect line at the manifold.
2) Plug that line from the water heater , turn water on and hopefully confirm no leak (ie. no rotation of meter dial).
3) With water off, open all faucets, put a dry pan under each, and the use a compressor to blow out the line
on the downstream side of the cut line.
4) Whatever faucet or faucets the water comes out of should Id where the pipe runs to,.

 

[Reach4]

To quote all, click Reply to the right of Like. To selectively quote, highlight the stuff to quote, and ideally a Reply balloon shows like above. Then click the Reply. You can repeat for other sections. I find that the Reply balloon is more likely to appear if the window is narrower rather than full width.

For blocking pipes for troubleshooting, try searching for "pipe freeze kit" in a search engine. Big bucks. Rental? I doubt it.

 

[DW85745]

For blocking pipes for troubleshooting, try searching for "pipe freeze kit" in a search engine. Big bucks. Rental? I doubt it.

Good idea. Will check if I can find a rental one but like you say -- I doubt it.

 

[DW85745]

Found one out of state. $99 day / $250 week , but kicker is have to pay shipping both ways.
Can buy one for $500.

 

[DW85745]

/////////////////////////////////////////////
CAUTION --- DANGER -- MUST READ
/////////////////////////////////////////////
For those reading this and have the idea to go out and get some
bottled CO2, Nitrogen or whatever, to try and freeze the pipe,
you can die in less than 3 minutes if the pipe and you are in an
enclosed area.

 

[WorthFlorida]

....Solved the rattlesnake problem, but created one thick concrete slab.

A easier and perhaps safer way to chip the concrete is get a rotary hammer drill and drill a series of holes in the concrete. You can easily set the depth. Then with a hand chisel chip away or use a small chipping hammer so it doesn't get away from you and do more damage.
One my first post I was going to mention to look out for snakes and scorpions in crawl spaces but I figured you already knew that.

 

[DW85745]

WorthFlorida, thanks for responding.
Checked into small chipping hammer yesterday. Can rent one from HD.
The river rock that was used was 3 to 5 inches, so hammer drill is out as tough go drilling through rock without diamond and
even then, tough. Biggest issue as I see it is -- Spending a day getting an area around the manifold cleared out,
if the leak is another foot or worse yet 5 foot away, digging all that up would be a cat chasing their tail. Right now per my other post,
https://terrylove.com/forums/index....reign-material-from-running-into-joint.81761/
is getting some "best" solution answers. Then off to the races to get this fixed.