I find it interesting that just one hundred years ago you could still buy house plans that did not include a bathroom. The concept of indoor plumbing was pretty new and I suppose that for those with limited means or access to technology, or perhaps for those prone to the thrill of adventure, the indoor "necessary room" just wasn't all that necessary.
Best I can tell from what I've seen (I'm a realtor) and read (I like history), by the 1920s most new homes came with a full bathroom and by the '50s the concept of a master bathroom or at least master half-bath seemed to be catching on, but it wasn't until the '70s that having 2 full bathrooms seemed to become the norm. Nowadays, any house with only one bathroom is considered "functionally obsolete," yet there are plenty of people out there perfectly willing to live in these houses and share their most basic facilities. However, the first thing that most home buyers will do when encountering a one bathroom house is try to figure out how to squeeze at least another toilet into the landscape of the home, stomach bugs being what they are and all. It is one thing to have only one tub, but yet another thing entirely to really need to go when the only bathroom is otherwise occupied. This may explain why I've seen so many toilets in basements. By themselves. Lonely, but useful.
Our first house was built in 1926 and had only one bathroom. When we lived there only two of us needed to make any real use of it (other than for bathing, of course) while the other two were too young and undeveloped to catch on to the concept and need. Our second house was built in 1925 with only one bathroom, but long about 1939 a half-bath was added when a porch was closed in. (We know that it was 1939 or so because that was what was stamped on the underside of the toilet tank lid. Isn't that a nice little trick?)
It was a wonderful, awful room at all of 3x5 feet. The toilet had been placed so close to the wall that you had to sit on it sideways if you were taller than a toddler. You could simultaneously throw up in the tiny, adjacent sink, if necessary, making it an excellent oasis for the gastronomically challenged. Efficient? Yes. Comfortable? No.
Because the toilet had been manufactured long before green building, long before low-flow toilets and water saving devices, long, even, before the first Earth Day, it flushed with passion and style and authority. Our kids wore cloth diapers and it was customary to dump and rinse out the solid waste (AKA poop) before exiling the wads of cotton to the pail. The first time I used this toilet for such a purpose I darn near lost the thing in the fight. I had not before and have not since encountered such sucking force from a piece of plumbing.
Once you were done with your business, whether it was sitting or dunking, came the hand washing adventure. The sink was original as well with a hot faucet and a cold faucet and never the twain shall meet. This made for a brief and, at times, uncomfortable hygiene experience.
By far the worst part about this room was its location: on the exterior wall of the house (correction: UNINSULATED exterior wall of the house). There was no heat source. One day I got the brilliant idea of putting a thermometer in the room to get a read on just how cold it really was in there. The little red line never got above 40 degrees. Over time the flushing mechanism in the toilet broke and so, in order to flush, you would have to take the tank lid off, plunge your hand into seemingly near frozen water, and pull up on the flap. It was pretty close to using an outhouse. In the winter we just waited our turn elsewhere.
For all the frigid, cramped, broken down-ness about this room, I loved it. A lot of "firsts" (of which I will not elaborate for fear of certain estrangement) happened there. In September 1993 I found out I was pregnant in that room, thanks to the window sill that held my pregnancy test. I managed to give my kids baths in that teeny, tiny sink with the hot and cold faucets. More paint and brownie batter and mud were washed off of hands and faces and feet than I can now imagine. It took me a while to discover that the old plaster on the walls served as entertainment and a certain someone, with great pleasure, sat and peeled it away, while taking care of other business.
After we had lived in the house for 7 years we decided to remodel the kitchen. Involved in that was moving the half bath to an interior wall. We demolished the old and built in the new. It was a great new bathroom with it's own character built-in and for the next 4 years we actually gathered a few memories in that room as well. But there was something just so wonderful about that old bathroom. That wonderful, awful bathroom.