The paradoxical status of marijuana in the US—it is legal to grow and sell in some states, but remains illegal under federal law—makes it hard to regulate. In theory, Californian state or local regulators should be able to set environmental standards for cannabis cultivation, the way they might with grapes or timber. But the federal government won’t let them. As a result, growers enjoy unregulated use of water, and the resulting easy profits have helped attract operations that are increasingly industrial in scale—and run by growers who are unrepentant about sucking California dry. [Source] [BJS]