Many farmers rely on groundwater, especially in dry years. Some Southern California cities also get as much as half of their supply from wells. But no California agency has been tracking exactly how much is used or who uses it, even though nearly every other state regulates this resource.
The free-for-all has led to farmers in many areas pumping groundwater faster than the natural recharge. Water tables have rapidly dropped and, in some communities, homes have run out of water. During the 2012-to-2016 drought, about 3,500 domestic wells went dry.
Also, when coastal aquifers are heavily tapped, saltwater creeps inland. In central and Southern California, water managers have to inject freshwater into aquifers to stop saltwater intrusion.
San Joaquin Valley farmers have pumped so much water that land in some areas have subsided by 20 feet or more. This damage cannot be undone, and the water storage capacity is lost forever.