Slimming down a $17 billion plan to shunt water from Northern California to the arid south has the state considering ways to supplement water needs. Desalination is one of the methods getting some attention. California has a water problem, drought or no drought. The new administration has signaled a shift in water policy by specifically talking about turning salty water potable after Gov. Gavin Newsom (D) said he would support only a single tunnel as part of the project known as WaterFix, rather than the two tunnels his predecessor pushed for to bring water to the state’s southern half.