Altas Obscura tells us about the S.S. Relief--the formal name for an outhouse that floats in Lake Casitas near Ventura, California. The artificial lake is an important water reservoir for the thirsty people of southern California, so the Casitas Municipal Water District takes its cleanliness very seriously.
The lake is popular among boaters and fishermen. After a few hours out on the water, people need to relieve themselves. They can then paddle up to the S.S. Relief, which is a 2-seater outhouse that floats on the surface of the water. The waste is contained on the barge, so there's no contamination of the lake's purity.