Where copper meets galvanized pipe

[Goodbar]

I'm looking to avoid unexpectedly ripping apart my kitchen and bathrooms due to galvanic corrosion in my 1930s colonial. There are two galvanized Tees in the basement between copper pipes on the cold side only. One feeds the kitchen sink, with the other leg going to the laundry sink. The other is for the riser to the 2nd floor bathrooms, plus supply to the water heater.



The Tee for the kitchen has considerable external corrosion, but the other one looks fine. No problems with water pressure or flow anywhere.

After some web searching it looks like I could add dielectric unions or nipples, but there isn't a consensus that they actually work. If I were to add one or the other, I would move the laundry sink to a new Tee on the copper pipe and plug the galvanized Tee.

Suggestions on how to proceed (or abort!)? If I busted the kitchen Tee, I have reasonable confidence that I could run a new pipe as was done on the hot side. Not so for the riser, which would require access in the wall or ceiling.

Thanks

 

[Terry]

I use 6" long brass nipples. I don't bother with dielectric unions. They close off too soon.

That being said, it's why many plumbers when doing a repipe plan on replacing everything. Whatever is left is just temporary at that point. It ain't getting better.

 

[Sponsor]

 

[Dj2]

What Terry is telling you is: time to replace everything.
It may look expensive but it will be cheaper in the long run, plus you will have cleaner water!

 

[Goodbar]

Thanks for the input. We want to remodel the kitchen in 3-5 years and it would be much easier to access everything at that point. I definitely want to get rid of all of the galv pipe and am amazed that a previous owner only had the hot side done. I suspect a pipe froze and insurance only covered the pipe that froze... but so shortsighted to not do both while there's access. Anyway.

 

[Goodbar]

Put another way: If I can extend the life of the remaining galvanized pipe for < $50 in parts and a few hours of my time, that's cheap insurance until I'm ready to pay a professional to do it the right way. But if it's not going to matter at this point, I'll move down the list!

 

[Terry]

When I do repipes, the hot side is the first to go. Often they can no longer take a shower, or flow from the hot side has just gotten really bad. Sometimes the homeowner has asked about just doing the hot side, but the trouble with that is that then the new hot is going full bore and the cold side which tempers the water down is slower than a slug crawling across your grass lawn.
Also, once you're in there, it's hardly any more time to do both sides at once. Then for just the little amount more, you have finished with both the hot and the cold.

If you can wait it out until your remodel, sure, why not. Or if you're feeling it, it is just a few dollars in parts. I would leave the tee in place. I go from fitting to fitting on situations like that. The actual pipe may be missing part of the threads, and sometimes too soft to put a wrench on.

 

[Sylvan]

Dielectric nipple can help if your against a dielectric union

 

[Goodbar]

Out of curiosity, I checked the voltage between the corroded Tee and copper and got 0.3-0.5 V. Wasn't expecting such a high reading! I got nothing for the other one that looks fine externally.

 

[Goodbar]

Update: I tried to salvage that original galv Tee, which was a mistake! It was seeping though the body of the tee and getting the joist damp.

So now it's repiped with copper and it wasn't as difficult as I'd initially thought. Bigger hole to patch under the sink, though. I slid some rigid foam behind the pipes (against the exterior brick-on-block wall) and will foam it for a good air seal. I elbowed the cold pipe out of the wall lower than the hot to clear the trap next to the disposal.

Thanks again for the advice.