Can somebody give me a quick run down. I am going to change my Galvanised to copper. 1" main, currently I have already done the water heater in 3/4, what about the pipe going to the kitchen sink and dishwasher? bathroom sinks? I have a 2 story with 2 bathrooms upstairs, 1" or 3/4 up to the bath's then 1/2????????
How many fixtures do you have? It sounds like you have two full bathrooms, a kitchen sink and a dishwasher?
In that case I'd use 3/4 trunk lines and branch off with 1/2in for individual fixtures. A 1/2in line can have two fixtures on it, so a bathroom needs a 1/2in hot line (shower and sink), and a 3/4 cold line (shower, sink, toilet). Most people just run both in 3/4 though. Your kitchen sink and dishwasher can share a 1/2in line. Hose bibs should be 1/2in and not have any other fixtures on the line.