I am near the end of a kitchen renovation. Yesterday I was looking at some pictures taken at an earlier stage when I noticed a rust stain on the cold water pipe that supplies my kitchen sink (photo attached). I have since covered this pipe with drywall, but I'm wondering if it's worth cutting a hole to do a quick repair. It isn't leaking now, and I saw no evidence of water damage, but is this a problem waiting to happen? After I put up tile for the backsplash, any repair becomes a much bigger deal, so now would be the time.

I'm also wondering why I didn't notice this back when the wall was open, but I think the glare of the flash probably makes the stain more noticeable in the picture. Plus there were
A lot of things happening at that point -- I wasn't really focused on that pipe.

Finally, I'm wondering how a stain like this forms. Leaks don't usually fix themselves, so if this was ever a leak, why isn't it leaking a whole lot by now? If its condensation, why just the one spot?

If I do go ahead with a repair, I'm thinking in terms of epoxy rather than something more major (which would require more demolition and probably a pro). But any suggestions or opinions are welcome.

Thanks,
JH

P.S. Also bear in mind my house was built in 1905, my basement is full of dodgy old pipes that could stand replacing. But this one worries me more because it's a supply pipe, not a drain, and it's behind a wall. Who knows what else is behind my walls, but I know about this one. Thx JH

Usually a leak occurs and a small amount of water seeps down the pipe forming he rust, This leak was probably cause by not having a pipe sealant on the threads of the pipe and the fitting. It is possible for this to remain like it is for many years without leaking but it is also possible for one good jar from outside source and it may leak. So you got to use your own judgment. I don't think that an epoxy would be a good fix for the same reason, the jar for an outside source.

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Originally Posted by letmetellu

Usually a leak occurs and a small amount of water seeps down the pipe forming he rust, This leak was probably cause by not having a pipe sealant on the threads of the pipe and the fitting. It is possible for this to remain like it is for many years without leaking but it is also possible for one good jar from outside source and it may leak. So you got to use your own judgment. I don't think that an epoxy would be a good fix for the same reason, the jar for an outside source.

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Thanks for your response. Is it likely that I'd be able to fix this simply by unscrewing the fixture, adding sealant, and screwing it back on? Or would I need to replace/rethread the old pipe? Obviously I won't know for sure until I take it apart, but I don't have any experience with threaded pipe so I'm trying to get a sense what I'm getting into. Thanks again JH

Leaks may not fix themselves, but they do lime and rust enough to slow the leak, perhaps to where the water dries up as fast as it leaks. Then years later, they jump up and bite. I would hate to own a house with 100+ year old galvanized pipe. I am surprised it is in as good of shape as it looks. To take that apart and fix it, you might have to rip out quite a bit of pipe including removing the fixtures, or cut 2 of the pipes and rethread them for unions. You start taking old pipe apart, it is far too easy to turn into a bigger project. I really think you need to bite the bullet and repipe the house. I do all my own work, and encourage others to what they can of their own. I think this project is over the line to where you should call a pro.

For epoxy or something to last very long, you would need to sand blast to bare metal.

I would replace it before covering it up for good.

The most quick and cheapest fix would be PEX tubing.

As for galvanized steel pipe leaking and rusting itself shut, that isn't as uncommon as you think, the leaks generally happen along the welded seam of the pipe, and are usually just pin hole leaks that may in time rust themselves closed from the outside in -- You can hasten this action by wrapping the leaking section of pipe with a soaking wet rag.

However, I wouldn't suggest you do this, especially if the pipe is to be buried inside a wall.

Thanks all for the suggestions. Just to clarify, I don't think the galvanized itself is 100 years old. But there are other pipes in the basement (like my cast iron stack) that just might be. I'm really not sure, but the stack is definitely older than the galvanized.

For what it's worth, the stack itself, though old, looks OK, and doesn't appear to be leaking. Obviously I don't know what's behind my walls, but it will require an awful lot of demolition to find out. I'm not quite ready to gut the whole house, so I'm working in stages and dealing with things as they come.

If you would be interested in just replacing the leaks that you showed in the picture I have an idea. There is a fitting called a G-coupling. And this is how I would use them. On the pipe going up from the tee I would cut it with a hack saw about six inchesabove the tee, not an electric saw, the electric would cause too much vibration and could create more leaks. I would also cut the pipe going down also about six inches below the tee and then I would cut the 1/2 inch pipe about ten inches down for the ell, I am saying for you to make the differences in the pipes so that the fitting you are going to use will not be in each others way. After you have the old pipes out I would get a 3/4 inch G-coupling and slip it up on the upper pipe, another G-coupling on the lower pipe. I would then use a galvanized tee and a galvanized street ell, plus one 1/2 inch nipple to go down to the point where you cut the pipe I would use a 1/2 inch G-coupling there. And then the two six inch x 3/4 inch nipples in the top and the bottom of the tee slip the G-couplings into place and tighten them up. Make sure that you use some kind of pipe joint compound on the joints.

Have you ever changed a diaper on a baby? It is frustrating because you know that in a short time you going to have to do it again. Repairing leaks on old galvanized piping is like that. If you cover a wall that has a known leak in it, and that is what you have, then you are begging for problems. That picture represents a rotted thread that is barely holding on and is only together because you have not bumped it hard.
As much as I so often do not agree with labman, I am totally in agreement with repiping.

OK folks here's my dilemma. If I were committed to this house for the long haul, then I agree that replumbing the whole thing would be the clear choice. Along the way I would rethink the layout of the kitchen, put in a full bath upstairs (currently we have half), and extend the rear of the house to make room for all the above. It would take months and cost in the tens of thousands (or more, I really don't know), but the result would be a really great property.

Problem is, we expect to relocate in the next few years, so we just can't justify that level of investment. The next owner might gut the place, or tear it down and start over. It's impossible to say, and I hate not knowing whether any improvements will be wasted.

Which leaves me in the land of imperfect choices. If we don't do all of it, is it worth doing any? As a result we have limited our renovations to immediate improvements like adding a dishwasher, and fixing things that are obviously broken.

Repiping this particular line, however, might be an option. Does anybody know whether PEX meets code in Chicago?