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Time to replace galvanized where meeting copper?


I recently noticed some rusty deposits on the top of my water heater, so I looked up and discovered the galvanized pipes are connected directly to newer copper pipes. I understand this is not a good idea unless a dielectric union is used because corrosion occurs quickly. My question is, how "quickly" does it occur, and should I make it a priority to replace these fittings ASAP? Should I replace with dielectric unions, or should I replace ALL of the old galvanized pipes?

The galvanized plumbing is from 1951, so it's going on 60 years old. Most of it is exposed in the unfinished basement. I found about 4 places where the old galvanized pipe is fitted with newer copper piping, and attached some photos here. They all look like they are corroding. I'd rather not wait for a leak to develop, but I also don't want to be hasty in incurring the expense of replacing the galvanized pipes all the way back to the street if I don't need to. Is it better to replace with copper or PEX?


Re: Time to replace galvanized where meeting copper?

Well...that certainly doesn't look good. I think it's nearing the time when you should be replacing the galvy.

Direct copper to galvy isn't advisable for the very reasons you see before you. (However, just how big of a no-no it is really depends upon the composition of the water involved. There are many houses around here where this has been done over the years without any consequence. Those connections have been there for umpteen years and are just fine yet today. Obviously, in your locale with your water...it shouldn't have been done. And it is always safer not to do so.)

Whether you should replace with copper or PEX...depends. You can find good arguments for each and it's impossible to say from here which way you should go...as more info (particulary about the supply water) would be needed to make a judgement call.

If your particular water is aggressive toward copper, then PEX is for sure the way to go. If the water isn't particularly aggressive towards copper, then copper may be a good choice as it has its advantages also. (The price of copper has finally dropped back to reasonable levels recently...which was a major driving force around these parts toward the use of PEX so long as copper remained expensive.)

Bottom line....can't tell you from here which one I would choose without more info, but something should be done before too long from the looks of it. (within a year or two... max...but that's kind of a guess too cause we dont know how long it took to get where it is today. The remaining pipe walls may be thinner or thicker than one imagines. You'll know you waited a bit too long when one pops a leak. )

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