The San Juan Water District showed the rest of California how to save water when the state needed the savings most. The supplier for eastern Sacramento and southern Placer counties cut consumption 41% from 2013 levels during the summer of 2015 — the height of a years-long drought. District residents let their acre-sized properties fade, livestock went thirsty, vineyards decayed. Then, the rain arrived. Regulators relaxed the rules and on went some spigots. This summer, the district used almost 600 million more gallons than it did last summer. Lacking a state mandate to conserve, residents’ daily consumption climbed to more than 500 gallons per person.