A little confused on this aspect of the credit....I was told buy a colleague that this credit can only apply to newly installed fixtures? and not base building restrooms that were not modified? Please confirm because I was under the impression that you can use the base building un modified systems that serve the office space even if not part of the Commercial Interior remodel...In fact since that is what the tennant is using, Thats is what you have to make the calculator for. *As long as it meets or exceeds water sense.  Please help. And is it also a requirement that you use alternative water sources? Just a little confused on this credit...Thanks for invite you can give me!   This is for a v4 ID+C : commercial Interiors project.