what is this?

[Mark Krajcar]

White powdery stuff on the cold water copper pipe. My guess is that is mineral deposits from a tiny leak at the joint.

[Rick Cantrell]

White powdery stuff on the cold water copper pipe. My guess is that is mineral deposits from a tiny leak at the joint.

Likely, yes

[John Kogel]

The cheap brass fitting probably has a pinhole in the casting there.

[Mark Krajcar]

Thank you for the redponses!

[Lon Henderson]

I see this constantly around here. Water is "eating" its way out from the inside off the valve. In the past when I was trying to figure out how big a problem these were, I would knock the blisters off. Several times, water started dripping out. It can take many years for these blisters to finally start leaking, but they are still ticking timebombs even if slow ones.

[Craig Barr]

When I see these, the brass fitting was probably made in China. I have seen more failures in brass fittings from China than Carter has pills. Spend the extra 50 cents and get one made in America


I see this constantly around here. Water is "eating" its way out from the inside off the valve. In the past when I was trying to figure out how big a problem these were, I would knock the blisters off. Several times, water started dripping out. It can take many years for these blisters to finally start leaking, but they are still ticking timebombs even if slow ones.

[Jim Hintz]

When I see these, the brass fitting was probably made in China. I have seen more failures in brass fittings from China than Carter has pills. Spend the extra 50 cents and get one made in America Better explain who "Carter" is Craig, there's lots of young'uns on here ! :D

[Rod Butler]

. . . . but they are still ticking timebombs even if slow ones.

Time-bomb may be a bit harsh. :D