When I first moved to VT I worked in a walk-in closet that was above a laundry room. Ran pipes & drains up to it. It was tiny, but functioned quite well for those first few years- until I could build my current space. It was L shaped, went around a chimney. From the door, the sink was on the left, about 6' x 15" just big enough for 11x14 trays. past the chimney on right I had the enlarger in the foot of the L.
I'll agree water makes everything simpler. My first darkroom in '82 was a black plastic wall in a bedroom with an adjoining bathroom (the only bathroom in the apartment I shared with two others). Not always easy.