It really isn’t farfetched to think that drought can completely erase a water supply for large cities.  A 50-wagon train is traveling 212 miles every week to deliver water to a population of a half a million people right now in Latur, India. They are out of water after four years of drought!  When you know something like this can happen, it is best to correct your behavior before catastrophe develops.  California’s Sustainable Groundwater Management Act offers an approach that balances water demand with surface and groundwater availability, every year. It's all about adjusting to the available water resource not the other way around.