edu intent: your thoughts as to cause

cold supply valve @ wh w/calcification
no leak present although it looks it




Condensation on the cold water line. Looks like they installed insulation on some of it but where it meets the valve there is none.

Ummm…Faulty (way south of the border) Brass???..:stuck_out_tongue:

I would say it was leaking and sealed itself up.

The fact the ground conductor has “patina” supports the condensation/prior leak theory. Looking closely, I suspect it may have been cleaned of some of the buildup at some point.

If stray electrical current travels through a copper water main it will usually rot out in a year or so and then leak.

That looks like it may be a electric water heater and there is a ground there as well.
If this is being caused by electroysis I would add a dielectric coupling so the rubber could act as an electrical break.

Spray some battery terminal cleaner on it and call it a day… :wink:

IIRC from my plumbing days, brass is universal and can be connected directly to copper or steel piping without a separate dielectric. BTW: dielectric couplings are only minimally effective at reducing galvanic corrosion because the water inside the pipe is, itself, an electrolyte

Methinks its a porous brass casting that leaks through the pores at a microscopic rate. Possibly due to dezincification or just poor casting. It’s close enough to the heater that the minuscule amount of water that gets through evaporates, leaving the dissolved minerals from the water behind. I see this often in Texas attics.

I think the green on the bonding wire is due to exposure to the acid flux from the adjacent sweated joint.

Thank You…:wink:

Agree with Chuck, upon looking at pic 2 there was moisture below and from the direction of the build up it appears to be coming from the threaded fitting with the nut (left)…maybe just needs tightening or…maybe ready to blow. JMO