It’s the most frustrating part of conservation. To save water, you rip out your lawn, shorten your shower time, collect rainwater for the flowers and stop washing the car. Your water use plummets. And for all that trouble, your water supplier raises your rates. Why? Because everyone is using so much less that the agency is losing money. That’s the dynamic in play with Southern California’s massive wholesaler, the Metropolitan Water District, despite full reservoirs after two of history’s wettest winters. … Should water users be happy about these increases? The answer is a counterintuitive “yes.” Costs would be higher and water scarcer in the future without modest hikes now.