
About Watermaster
Introduction
The Main San Gabriel Basin is one of several adjudicated groundwater basins in California. On this page, we are sharing the story about our mission, jurisdictional area and its history, our responsibilities and functions, and our people, as well as current and archived legal notices.
Our Mission
Our mission is to administer and enforce the provisions of the Judgment which established water rights and the responsibility for efficient management and the quantity and quality of the Basin’s groundwater.
Our Jurisdiction and History
Watermaster's jurisdiction overlies a portion of the upper San Gabriel River watershed and is defined as the “relevant watershed” in the Judgment where within which water rights are adjudicated. Here, you may view a map of the relevant watershed boundary and read a written legal description of the relevant watershed boundary.
> View Current Annual Report PDF
> View Amended Judgement PDF
Our Responsibilities and Functions
To fulfill our role and mission, Watermaster's primary responsibilities are to: ​ > Manage and control the withdrawal and replenishment of water supplies in the Basin. > Determine annually the Operating Safe Yield (the amount of groundwater that can safely be extracted) for the succeeding fiscal year, and notify the pumpers of their shares thereof. > Acquire and spread replacement water as needed. > Coordinate local involvement in efforts to preserve and restore the quality of groundwater in the Basin. > Assist and encourage regulatory agencies to enforce water quality regulations affecting the Basin. > Collect production, water quality, and other relevant data from producers. > Prepare an annual report of Watermaster activities, including financial activities, and summary reports of pumping and diversion. We operate under a formal set of Rules and Regulations, which spell out the procedures by which Watermaster-controlled actions are carried out. Under the Rules and Regulations, water producers in the Basin must obtain Watermaster approval for activities such as:  > Constructing or modifying a well. > Constructing a groundwater treatment plant. > Increasing groundwater extraction. > Spreading water in the Basin. > Spreading and storing supplemental water under a cyclic storage agreement.  In order to fund its operation, Watermaster is authorized to levy and collect assessments from the producers based upon their amounts of production during the preceding fiscal year. These assessments are applied primarily to the purchase of replacement water and to administrative costs.
Our People
The work of Watermaster is performed by our board, committees and staff. Learn more about them below:​