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A Groundwater Sustainability Agency (GSA) is a local public agency tasked by a 2014 California law, the Sustainable Groundwater Management Act, with developing and implementing a plan to achieve groundwater sustainability.

The McMullin Area Groundwater Sustainability Agency (MAGSA) is a GSA that was formed on January 31, 2017 when Fresno County, Raisin City Water District, and Mid-Valley Water District executed the McMullin Area Groundwater Sustainability Agency Joint Powers Agreement which officially formed MAGSA as a GSA.

MAGSA is authorized under SGMA to develop, adopt, and implement a Groundwater Sustainability Plan (GSP) for the sustainable management of groundwater in a portion of the Kings Subbasin.


The Sustainable Groundwater Management Act (SGMA) is a CA law requiring groundwater levels to be sustainable by 2040. SGMA’s goal is to allow local agencies to sustainably manage groundwater by implementing their Groundwater Sustainability Plans (GSPs).

Signed into State law in September 2014, SGMA provides a framework for local governments and water agencies to manage groundwater resources through the formation of GSAs like MAGSA.


A GSP is a roadmap for how a region will avoid the negative effects of groundwater overdraft and achieve sustainability by 2040. MAGSA actively sought landowner feedback during GSP development and continues to do so through the Stakeholder Committee and other channels. MAGSA’s GSP was adopted in 2019 and can be viewed HERE.

MAGSA is committed to securing a sustainable groundwater supply through collaboration with landowners and the implementation of innovative recharge projects.

Over the 20-year Groundwater Sustainability Plan implementation timeline, MAGSA is implementing projects like the McMullin On-Farm Expansion Project and Aquaterra Water Bank along with management actions like well metering to balance the estimated annual 91,000 acre-feet of groundwater overdraft occurring within the agency.


MAGSA is one of over 250 agencies in the State of California created and tasked with implementing SGMA, and one of seven GSAs within the Kings Subbasin. Learn more about Kings Subbasin coordination HERE.

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