Hello,

Have had a pinhole leak this year, and also a few years back, so started
looking at my Copper house water plumbing a bit.

Noticed several areas with that bluish-green coating on it.

a. Is this indicative of a pinhole leak developing ?

b. what actually is this bluish-green "stuff" ?

c. Is it a reaction of the Copper with the outside air, and thus
developing on the pipe's outside, or it coming from the inside ?

d. Interesting in that I see it in the middle of a run, here and there,
so it's unlikely that it is caused by any soldering flux residual.

I do also see it at joints, and am wondering if it is caused, here, by a
soldering flux residual ?

Any thoughts on the bluish-green stuff, and pinhole leaks would be most
appreciated.

BTW: how common are pinhole leaks in older (around 35 yr old) homes ?

Thanks,
Bob