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Welcome to the home page of the Main San Gabriel Basin Watermaster, an agency charged with administering adjudicated water rights and devoted to the management and protection of groundwater resources, within the watershed and groundwater basin known as the Main San Gabriel Groundwater Basin in Los Angeles County, California.

To learn more, please visiit 

Key Well Level


Historic Low:           169.4 ft.                        November 21, 2018

Historic High:          295.30 ft.*                               July 20, 1983

Current Level:         227.0 ft.                  As of September 15, 2023
                                                  Since entry of judgment, 1973

Legal Notices


Main San Gabriel Basin Watermaster



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