Is anybody familiar with why copper pipes are solid black 
Try here .
Black copper cold water lines- InterNACHI Inspection Forum](https://www.google.ca/url?sa=t&rct=j&q=&esrc=s&source=web&cd=1&cad=rja&uact=8&ved=0ahUKEwi3mJ-ht-TUAhXSDj4KHSYTCAoQFggiMAA&url=https%3A%2F%2Fwww.nachi.org%2Fforum%2Ff22%2Fblack-copper-cold-water-lines-2837%2F&usg=AFQjCNEqaKadr5kMLFO9gJfQRMx134y9WQ)
https://www.nachi.org](https://www.nachi.org/) › …› Specific Inspection Topics › Plumbing Inspections
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[FONT=“Arial”]Mar 19, 2006 - 15 posts - 6 authors[/FONT]
[FONT=“Arial”]Only once before have I seen copper turn black to thisextent. … The chemical reaction between the two metals eat a way the copperpipe.[/FONT]
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thanks Roy
If the cold lines are black and hot lines are not so black condensation has been one of the factors. Very common where I am, and nothing to get excited about, there has been no chinese drywall or any of that where I am, but I am in oil country, lots of oil and gas wells, refineries and gas plants all around, so I am thinking that is also a factor. I take it more as an indication that they need to do something about excess humidity in the basement in summer than any problems with the water lines.
There are a lot of knowledgeable folks on this forum and I would ask them if the presense of radon gas may turn the copper black? There is also a gas processing plant within 2 miles of my house and the escaping gas may be the culprit. Looking for input on this one. The house is 20 years old. All copper plumbing, water softener.