I was renovating my house and have to open up the ceiling. Once the ceiling was opened up I see that our copper water piping has some green deposit only on the joints. I was doing some research online and seem that the conclusion is mixed, some say not to concern while other think that it needs to be fixed. There is one or two drops of water on the joint where there is green. Do I need to worry and replace the pipe with PEX and copper fittings ? If I were to do something now is the time as the ceiling is open up. I have attached a picture for reference. Thank you everyone [ATTACH]74720[/ATTACH]

I'm in PA and my sewer line has decoupled from the 4" iron sanitary tee(?) going through my basement wall and it has sunken. Please see photos below: [ATTACH]74490[/ATTACH] . [ATTACH]74491[/ATTACH] . [ATTACH]74492[/ATTACH] I was surprised to find that the outer diameter of the iron sanitary tee coming through the wall was only 4-3/8" and the inner diameter is 3-7/8" ...I thought there would be a wide mouth (hub?) at the end for the next pipe to slide into. But the sewer lateral pipe looks like the same diameter! Here's a direct over-head photo of the two: [ATTACH]74494[/ATTACH] The sewer lateral pipe may look smaller but I think it might be an optical illusion since it sits much lower ...but I could be wrong too. I'm willing to dig and dig (about an 8 foot long trench) to raise the pipe up to meet the height of the sanitary tee but I have a few questions: (1) Once raised, how would I join the pipes together. A Fernco wouldn't fit in the tiny space between the two pipes would it? (2) How did they used to be joined together? I see no evidence of breakage or pieces of iron - the place was built in 1979. (3) Why did the builders in 1979 use PVC for all drains except for the iron sanitary tee going through the wall? It's not critical; I'm just curious. If I have to replace it, I'd like to use PVC and am wondering if it's not allowed or something. Thank you for any input!