My friend put a bathroom in his hangar in Glendale Az. The county inspected it and said the only problem was there was not a fan from the bathroom vented to the roof of the hangar. He said the door works perfect for venting. He lost, a fan was put in.
We wanted to put water/sewer in but city required that we put water collection system with oil separator for something like $6000 per hangar. Overall inspections and other requirements added 10% to the price.