Originally Posted By: wblakey This post was automatically imported from our archived forum.
Inspected a house today where the copper pipe from the main water shut off, bringing cold water into the house was completely black. It was not powdery, it was evenly distributed and the same age as copper pipe attached to the water heater which was a normal copper colour.
Can anyone tell me what turns copper black? I've seen it go green from corrosion, but never this colour before?
Originally Posted By: dhadler This post was automatically imported from our archived forum.
I have noticed it in many homes as well. In some places like the furnace room, all the copper lines are black. Doesn’t appear to be anything wrong with the piping itself, but it would be nice to be able to inform customers why it did that?
I've heard a few suggestions like if the laundry room is nearby, it could be from the soaps and cleaners used...soft water system salts...faulty furnaces, but nothing I've been able to call fact yet 
Still stumped in Alberta?
-- Darrell Hadler
Five Star Home Inspections
Medicine Hat, Alberta CANADA
Originally Posted By: wblakey This post was automatically imported from our archived forum.
Dean Call wrote:
It's usually caused by some chemical stored around the copper.
I've seen some pretty bad looking stuff when a swimming pool filter was inside the basement.
If that was the case, then wouldn't all the pipes be discoloured? In this case the cold water supply was black but the pipes coming out of the water heater were normal copper colour.
Originally Posted By: dvalley This post was automatically imported from our archived forum.
W Paul Blakey,
This blackening is simply caused from high humidity and moisture in that specific area. When the copper does tarnish it will first turn green and then to black.
It's not a big deal, but just for your information...It gets that way from being in a moist area such as next to the foundation area.
Originally Posted By: wblakey This post was automatically imported from our archived forum.
dvalley wrote:
W Paul Blakey,
This blackening is simply caused from high humidity and moisture in that specific area. When the copper does tarnish it will first turn green and then to black.
It's not a big deal, but just for your information...It gets that way from being in a moist area such as next to the foundation area.
No, this was different, the area was dry, there was normal humidity, the pipe was a uniform black, it looked almost like it had been spray painted. There was no greening of the copper at all.
I did receive this bit of information from an inspector who had seen a thread on another site a couple of years ago. He said...
Apparently it is due to electrical charges running along the copper pipes, typically due to improper grounding and/or bonding or bare electric wires laying on the copper pipe somewhere.
Originally Posted By: dvalley This post was automatically imported from our archived forum.
With electrolysis look for small pits in the pipes that will eventually turn into pin holes. There is a test you can perform to determine electrolysis but it is a bit invasive.
You can take an AC voltmeter and connect one lead to earth ground, (a rod the goes under the basement floor) and set the meter on 110 VAC. Then put the other lead on the suspected pipe and began to back down the meter settings. ANY READING you get indicates current is flowing and you, indeed, have electrolysis. You might want to remove the rubber insulation while you check so the pipes are back in the original configuration. You can then start insulating until you no longer get a reading.
Originally Posted By: wblakey This post was automatically imported from our archived forum.
Hi David,
First of all I have to say that for someone so young (your photo) you certainly have some great advice. 