For more than a decade, 57-year-old roofer and writer Joseph Jenkins has been advocating that we flush our toilets down the drain and put a bucket in the bathroom instead. When a bucket in one of his five bathrooms is full, he empties it in the compost pile in his backyard in rural Pennsylvania. Eventually he takes the resulting soil and spreads it over his vegetable garden as fertilizer.

“It’s an alternative sanitation system,” says Jenkins, “where there is no waste.” His 255-page Humanure Handbook: A Guide to Composting Human Manure is in its third edition and has been translated into five languages, but it has only recently begun to catch on. His message? Human manure, when properly managed, is odorless. His audience? Ecologically committed city dwellers who are looking to do more for the earth than just sort their trash or ride a bike to work.

“It’s one of those life-changing books,” says Erik Knutzen, 44, an eco-blogger in Los Angeles. “You read it, and the lightbulb just goes on.” Now he eschews his porcelain potty for a big bucket with a toilet seat. He “flushes” by tossing in a scoop of sawdust, which not only neutralizes smells but also helps speed the breakdown of material for compost. Like many back-to-basics sophisticates, he believes Jenkins’ humanure system is more sanitary and more rational than the conventional alternative. “Human waste is a perfectly good source of an important resource, nitrogen,” Knutzen observes. “Water is a valuable resource too. Why mix the two and turn all of it into a problem?”

Wastewater treatment is much more energy-intensive than composting, which needs little more than time (about a year) for complete decomposition and pathogen elimination. In Austin, Texas, a sustainably minded nonprofit called the Rhizome Collective succeeded this year in getting the city to approve what may be the first legal composting toilet in the U.S. “The hypocrisy is amazing,” says Lauren Ross, 54, a civil engineer involved in Rhizome’s four-year battle to get a permit. “The city will buy you a low-flow toilet, but they’ll fight you all the way if you want to build one that uses no water at all.”