I've been surprised to see floorplans from the 1870s that included an indoor bathroom. The plans shown below are for a "Residence of a Country Physician" from 1878. Although I have never been able to actually pinpoint a date that indoor plumbing began to commonly be used, there might be evidence that suggests that homes and buildings were beginning to be plumbed during the Reconstruction era (~1865-1877). Wealthy families could probably afford such luxury, but the majority of the population still used outhouses for decades after indoor plumbing was introduced. It was just an added cost for building a house. My mom can still remember using an outhouse as a child whenever her family went up to the cabin that her father built, and that was in the 1950s! There are still remote places in America that don't have indoor plumbing, but obviously they are not the norm.
In this plan, there is a lavatory off of the consultation office on the first floor, and a full bathroom on the second floor in the same position. The description of the plumbing in the house is taken from the webpage:
"The matter of drainage to be properly arranged, and there being a running stream in the rear of lot, the Doctor congratulated himself that he would not live on sewer gas. Yet the drains must be well ventilated and a trap placed in main pipe just clear of the house. This, the Doctor said, if good for nothing else would keep the rats from entering the house by the drains."
This is just one way that Pinterest has been a learning tool. I'll share more in upcoming posts about what I've learned on other topics, but until then, feel free to browse my Pinterest boards!