green crystallized matter on copper pipe

What would cause one side of a soft water loop to have a thick amount of green crystallized matter on the copper pipe? I could not see if there was a dissimliar metal attached to the copper that would have cause this or would a leak have caused this buildup? thanks.

Active leak and corrosion.


It’s called verdigris, not to be confused with ambergris.

If it’s crusted up like the picture William is showing, it’s seepage from a leak.

If it’s only a light coat of this substance, it’s usually caused from flux build-up that the plumber never cleaned off after soldering the connections (some Plumbers are actually lazy). They’re suppose to clean the soldered area with steel wool once they’re completed with soldering.

Acidic water is needed to cause that much corrosion in connection with the slow leak.


One example of a patina is a green surface texture created by slow chemical alteration of copper, producing a basic carbonate. It can form on pure copper objects as well as alloys which contain copper, such as bronze or brass.

Exposure to chlorides leads to green





1 a**:** a usually green film formed naturally on copper and bronze by long exposure or artificially (as by acids) and often valued aesthetically for its color

Similar to a copper roof turning green after 7-10 years of acid rain on it.