In 2013 I posted a problem I had with a rental condo unit where the copper drain line was leaking.

I initially discovered it because I could hear drip drip drip whenever I turned the kitchen faucet off. Being that the drain/supply lines are located inside the wall cavity between my unit and my neighbor's unit, I ended up cutting a hole on the side of the kitchen cabinet, the other side of that being the bathroom.

This is the inside of the kitchen cabinet where I cut a hole back then.



In this picture, you can see to the left my bath tub, and to the right the neighbor's tub waste and overflow pipe. You can also see the bottom plate is all wet.



The ideal place to make the repair is on the bathroom side, however that is all tiled unless I want a major renovation. Here is a picture of the bathroom, the wall around the tub are all tiled and the drain pipe runs behind the tub, about 24" above the slab.

I was stuck with trying to make the repair from that access hole in the adjacent sink cabinet, where I cannot even see the leaking pipe.

My approach back then was to lay on my back inside the sink cabinet, with my right arm sticking as far into and up that hole as possible, holding my phone camera pointing up and randomly press the capture button and took many many pictures until I found one that gives me a clue where the leak is occurring.



I found a few useful pictures indicating the underside of my 1.5" copper drain pipe has holes.









I then used a sand paper and sanded smooth the bottom of the pipe for a better look. Definitely the sanded pipe shows the holes better.





Bear in mind I cannot directly see the pipe, I did everything blind with my body twisted like a pretzel inside the sink cabinet and verify afterwards with a phone camera.

At the time I decided to do a patch, I mixed up some plumbing epoxy (the kind that is like "play dough" and put that on the underside of where the pin holes were.



I tested it and no more leak.

I knew it's not a permanent fix, and eventually I have to replace the entire pipe. Every three months I visited the tenant and I opened that access hole to check for leaks, no leak for a while.

Until today when I went to fix the kitchen faucet. I heard a "drip" after the faucet was turned off.

So I opened up the access hole again.







The bad news is the leak is back. In almost the same spot.

The good news is I was turning on and off the kitchen faucet running it for some time and all that time the leak is minimal. Only a few drops, unlike four years ago it was all wet inside.



Repeating the same process using a phone camera, I took some pictures of the patched pipe and I can see where the new leak is.



A close up showing the water dripping off that spot.



It is very slow. I had the faucet running for 15 minutes continuously with the disposer on and off and as far as I can tell it did not get any wetter. Although I didn't try running the dishwasher that would drain into the kitchen disposer with more water.

Suggestions?

Put more play dough at that spot?

how about a 1 inch long piece of 5/8 ID rubber hose? cut a slit in it, wrap it around with the slit on the opposite side and hose clamp it tight.
makes a great temp patch that will last for years.

How about our buddy Phil Swift with Flex Seal - [www.getflexseal.com]

I have no experience with - just a idea - maybe good idea and maybe a bad idea.

Get a can and spray it........of course it will get on everything....I think you said you have to do this blind.

Packy, as you can see, there is a 1.5" horizontal pipe next to it that belongs to next door unit which has a mirror image layout. There supply pipes hot and cold vertical at that spot, then there is a tee, which cross on top of it to the bath tub spout. There is literally no room to put anything around that pipe due to it being so crowded and anything had to be done with one hand blind.



In addition, I have messed up the pipe by putting epoxy at the bottom, so the pipe is now totally out of round on the bottom, which makes a hose clamp type seal impossible.



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I am going to split this thread into a short term solution and a long term solution thread.

Curly, as a short term patch the Flex Seal may work. I have never used it but I am guessing Flex Seal is kind of like roofing tar?

I know it can be painted on or sprayed on.

What I think I will do is I will bring a quart size empty can next time and put it right under that spot and go back in a week and see how much water is collected to give me an idea.

At this point for a patch I guess my only option is more play dough epoxy, or something like Flex Seal.

I have seen some pipe wrap that is supposed to harden into epoxy but again with limited access and tight space with all kinds of pipes next to it I won't be able to wrap anything around it.

As a long term solution eventually I have to replace that whole pipe.

Obviously I cannot do it now because the unit is occupied and to replace that pipe I need to open walls and not something I can do in a day or two. So I will wait till the current tenant moves out - the lease does not end for another eight months.

My thinking is, having pin holes probably mean that whole pipe may be in bad shape so I need to replace that pipe from the kitchen stubout all the way to the sanitary tee connection. Here is a picture of the bathroom showing where the 1-1/2" copper drain is behind the wall.



Here is a plan view of the same thing.



The 4" CI stack is right between the toilet and the lav sink. The total distance between the stack and the kitchen stub out is 6.5 feet.

First, I need to open up the back side of the kitchen sink cabinet and free the stub out to the kitchen drain and cut the elbow.

Next, I will pull the toilet to get it out of the way, and open the wall there from the right side of the lav (exposing the 4" CI stack and the sanitary tee connection), to the left side of the bathtub so as to not mess with any wall tiles.

That should expose 24" of the horizontal copper pipe. I should be able to disconnect the pipe from the sanitary tee, then make a cut to remove 24" of pipe. Then I will slide the pipe to the left, make another cut, and repeat until the whole length is out. The only thing I can think of is if the pipe running through wall studs is clamped or strapped behind walls and I can't slide it out, I would be in trouble.

Once I slide the pipe out, I will try to put in new 1.5" PVC pipe in 24" sections and push them to the right and solvent weld one section at a time. Again, this may not work if the holes or notches in the wall studs are too small to accommodate 1.5" PVC couplings which are significantly bigger than copper. If that happens then I will use copper pipes and solder in sections at a time.

I know the sanitary tee connection is a rare fitting because both unit's kitchen drains are running in the same direction at the same height like a double barrel shot gun. So that is a double barrel sanitary tee (not sure what the proper name is).



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Agree, dry it off and lather it up with Flex Seal or equivalent. Put a qt-sized painter's pail at the site of the drip to keep the framing dry, and empty the pail every 3 months when you come to inspect.

Why not more JB Weld?

hi, I was debating that as well.

I could put more of the jbweld style epoxy. After all, it did solve the problem for 3+ years and still today it is better than it was when I first discovered the leak in a sense that it is a much much slower leak now.

I was expecting the leak to come back. If you see the picture of the epoxy patch I did I applied a wider area over the pin holes because I couldn't see the holes and had to do everything by touch.

I kind of expected the holes at the bottom of the copper to widen, and eventually the bottom would disintegrate enough and the leak would come from the edges of the epoxy and drip from there. But it didn't. The picture clearly show dry all around the bottom of the pipe except where the water is dripping from, so the water worked it's way though the existing layer of epoxy. That's a surprise.

Sum, the white outlined area looks like a water stain(kind of brownish color). There's 2 dark spots and white residue in the copper at the edge of the epoxy(red circle). Maybe holes?

steve, you may be right. will copper pin holes have white residue? I know the original pipe bottom looking at the holes were probably "paper thin" so it doesn't surprise me more and more holes develop.

I would need to have a better look and take another shot (actually 100s of shots) with my camera and see if one would show me a clearer pic from a better angle. The problem I keep getting is not only I had to blindly point the camera in that wall cavity, I had to press the "take picture" button with a touch screen but many times my finger touched the wrong part of the screen, it ended up zooming or exiting or whatever. Being inside the wall the camera doesn't have enough lighting even with a flash light I put inside so good focus is hard to come by.

Sum, if you are interested, and have an Android phone, look at one of these boroscopes:

[www.amazon.com]

Just bought this and it's a great buy for $20. The cable is like 20' long, the camera is waterproof, and you view on your phone. Once you are in position you snap a pic, or record video if you like. Will give you a much better idea of what's going on that stuffing your phone blindly up there hoping to get the right pic.

I'm also with Steve, the water is not leaking through the epoxy, it's leaking at the edge of the patch and running down.

Sorry double post



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