The “Paso Robles Area Subbasin” of the Salinas Valley Groundwater Basin (locally referred to as the “Paso Robles Groundwater Basin” - see DWR Bulletin 118 Basin No. 3-4.06), lies in northern San Luis Obispo County and extends into Monterey County. The subbasin is bounded by the Santa Lucia Range on the west, the La Panza Range on the South, and the Temblor and Diablo Ranges on the east. The basin overlies approximately 505,000 acres (790 square miles).
In 2015, the State legislature approved a new groundwater management law known as the Sustainable Groundwater Management Act (SGMA). SGMA requires that high and medium priority basins comply with the new law. DWR designated the Paso Robles Groundwater Basin as a high priority basin and designated the basin to be in a "condition of critical overdraft." The map below shows those areas subject to SGMA.