In theory, you can have accelerated corrosion at the junctions, but I
wouldn't worry about it too much.
I've taken some piping out on rehab jobs that were pretty old, and the
corrosion wasn't a big deal.
You could check the joints in ten years or so, and if you see anything going
on, you can always
change out to dielectrics then. The galv pipe is more likely to fail first
due to calcium clogging.
Bill
wrote in message
oups.com...
Hello,

I had a question/concern. I have a 60 year old house that I recently
had the majority of the plumbing replaced on. The house is small with
just one bathroom/kitchen/spicket/utility tub to supply. This weekend,
I had everything replaced but the horizontal pipes, since they were all
in good shape and made the job much quicker/easier (cheaper). The
charge was only $1200 to install the new copper, and now I'm a bit
concerned after reading about connecting galvanized pipes to copper.
There are four spots where this was connected directly - the kitchen
(hot/cold) and the shower (hot/cold). The water main and the water
heater both have dielectric unions to prevent the materials from
corroding.

Anyway, everything is working great and in most areas, the pressure is
noticably better. I've read in some spots that connecting the two
metals will cause the galvanized pipes to deteriorate quickly, even if
the entire plumbing system is grounded. I have seen several cases like
mine where the connection was done in the same fashion (directly), but
reading phrases like "rapidly speeds corrosion" has me a bit nervous
and wanting to just have the remaining pieces converted.

Any suggestions/input would be greatly appreciated.

Thanks!
Eric