The Mojave Water Agency (MWA) is one of the 29 state water contractors with access to supplemental water from the California Aqueduct. MWA's boundaries encompass approximately 4,900 square miles of the High Desert in San Bernardino County.  As a state water contractor, MWA is entitled to receive an annual allotment of up to 85,800 acre-feet of water from the State Water Project via the California Aqueduct. This facility extends south from the Sacramento Delta and runs locally through the communities of Baldy Mesa and Hesperia. The imported water supply is crucial to the area's survival because local aquifers have been in overdraft since the early 1950's, according to recent studies. For the past four decades, residents have been using more water than is replaced naturally.

The  Agency's essential mission was strongly reaffirmed with the conclusion of the Mojave River Adjudication. The Court's ruling notes that the Agency area continues to be in severe overdraft. The Court ordered the Agency to seek sources of water, including supplemental water, and to deliver that water in the most effective fashion to ensure the quality of life within its boundaries.

MWA was appointed as Watermaster in 1993 pursuant to the Court Judgment which adjudicated the rights to pump groundwater in the Mojave Basin Area. Watermaster's main responsibilities are to monitor and verify water production for approximately 450 parties (1,700 wells), collect required assessments, conduct studies and prepare an annual report of its findings and activities to the Court. Watermaster also acts as the clearinghouse for recording water transfers, maintains records for all such transfers and reports changes in ownership of Base Annual Production rights to the Court.