If there was no running water there was no indoor plumbing and thus no bathroom.

There was usually a small building perhaps 3 or 4 feet by 5 or 6 feet constructed about 50 feet or so from the back door of the house.  Sometimes the building had a little half moon cut into the front or perhaps the side.  The building’s door had a wooden or leather latch inside.

First a hole about 4 or 5 feet deep was dug by hand.  Next this building was placed over the hole.
Inside the building a platform about two feet wide the length of the building was built.  This platform was covered with wood and in this cover was cut a hole about one foot in diameter.  If the farmer was really prosperous the building might be twice as large and two holes, about 2 feet apart, were cut in the platform cover.  You had to be certain, when you dug the hole, that is downstream from where you dug the water well.

We had never heard of Cottonell or Charmin.  Sometimes corncobs were used or cornhusks but the preferred method was Sears Roebuck catalogs.

As an aside, many or most farmers ordered things from a Sears catalog.  It was much easier than going to town and the selection of items was better.  You simply wrote out your order, placed it in an envelope with a postage stamp (three cents I think in the 1930's and 1940's) and put it in your mailbox, which was on the road.  The mailbox had a metal flag which you raised.  This let the rural letter carrier know you had outgoing mail so he would stop and pick it up, even if no mail was being delivered to you.  About a week or two later whatever you ordered would be placed in your mailbox, or if too big to fit inside, just left by your mailbox.  No one worried about thieves then.

I am off on a tangent.  My mother died in 1948.  My father died in 1959.  He lived in town.  After his death, my brother my sister and me decided to lock up the house.  We could not find a key to the front door so we locked it from inside and exited the back door intending to lock that one.  The back door did not even have a lock. 

Getting back to the subject ... if you had to go at night, you took a lantern.  Animals or snakes might be inside.  After you did your business, sometimes you would spread some ashes or a little lime in the hole on the platform.

From time to time, as the need arose because there was no more room in the hole in the ground, another hole was dug and the outhouse moved to that location.  Of course, if you were out in the field or pasture when nature called you just went behind a tree and used leaves.  There were always flies around the outhouse.  Most people in town had indoor bathrooms, but even as late as the early 1940's some still had outhouses.

Oh, the joys of modern conveniences.