Important American inventors who contributed to the development of the toilet during the early 1900s included William Elvis Sloan (1867-1961), of Chicago, Illinois, and Philip Haas (1875-1927), of Dayton, Ohio. Sloan introduced the 'Flushometer' and was responsible for several flush valve designs. Haas obtained numerous patents for flush valves, flushing systems, and water closet designs. Indoor plumbing, including flushing toilets, was common in American households by the 1920s. Continue reading for more cool and creative bathrooms that geeks would love.