The water we use today has been used throughout eons, over and over again. In our county, about 40 percent of the water used is imported through the Sacramento-San Joaquin Delta. While nearly all of this water is from rainfall and snowmelt, a small percentage is used by several cities on its way to us and is returned to the system. Our Delta water supplies are treated at one of our three water treatment plants or filtered through groundwater recharge, making it safe to drink.