Last winter’s extreme storms notwithstanding, water remains scarce in California. Between climate change and ongoing growth, California can’t afford to squander a single gallon. Yet in Orange County, a project that could increase water supply by 50 million potable gallons daily has been awaiting approval since 1998. There are pros and cons aplenty to the $1 billion desalination plant proposed for Huntington Beach by Poseidon Water. And in the nearly 20 years during which state and local authorities mulled it, all have been masticated thoroughly.