The State of California is divided into nine hydrologic basins, each of which is administered by a Regional Water Quality Control Board (Regional Board). The mission of the Regional Boards is to develop and enforce water quality objectives and implementation plans that will best protect the beneficial uses of the State's waters, recognizing local differences in climate, topography, geology and hydrology. Each of the Regional Boards and a link to its home page is listed below.
Region 1: North Coast
Region 2: San Francisco Bay
Region 3: Central Coast
Region 4: Los Angeles
Region 5: Central Valley
Region 6: Lahontan
Region 7: Colorado River Basin
Region 8: Santa Ana
Region 9: San Diego