Having had no plastic bottles on hand, I set up a brazier and lit a fire in the bathroom. I used a frying pan to boil water, and drank out of my hands. The UI then prompted me (again) to select a container. I hit escape, and drank out of my hands. The UI then prompted me (again) to select a container. I hit escape, and drank out of my hands. I was soon slaked. This repeated until I elected to pour water on the ground. Only one unit of water was consumed from the toilet, uh, cistern.
Oh, and then the game promptly crashed.