We are obtaining a CO for a rear addition on our house from the 1960s (the previous owners never had a permit).. Anyway, we needed an electrical and plumbing certificate before having a building inspector do a walk-through... We got our electrical certificate, and it was like $500... Does anyone know how much it costs to get a plumbing cert? We are handing in the paperwork tomorrow and have to bring our checkbook, we just have no idea how much it's going to be