The links below provide more information about the Delta-Mendota Subbasin, Sustainable Groundwater Management Act and Delta-Mendota Subbasin Groundwater Sustainability Agencies.

Informational Materials

Additional materials will be posted as they are made available through the SGMA process.

General FAQs

  • What is the Sustainable Groundwater Management Act (SGMA)?

    The Sustainable Groundwater Management Act, signed into law in 2014, provides a framework for long-term sustainable groundwater management across California. It requires that local and regional authorities in medium- and high-priority groundwater basins form a locally-controlled and governed Groundwater Sustainability Agency (GSA), which will prepare and implement a Groundwater Sustainability Plan (GSP).

  • Is SGMA related to the drought?

    Not directly. Sustainable groundwater management, much like management of surface water resources, is the result of a long-term vision and commitment by one or more water users or communities. That said, now that the State has faced several consecutive years of drought, the need to manage groundwater is more relevant than ever. Some California groundwater basins have reached an all-time historic low. Creating a framework for state oversight ensures a standard, consistent process to maintain and actively monitor and manage basins at the local level, and reduce impacts seen from overuse of these basins.

  • Why was the SGMA established?

    Over the years, the California water managers, individual well owners, and communities that rely on groundwater resources have observed a rapid decline of water levels in some aquifers. Impacts and issues related to the decline is apparent. For example, some wells in California have experienced declines in excess of 10 feet during the drought and increases in groundwater pumping have exacerbated some areas of land subsidence, which also threatens infrastructure such as roads, canals and bridges.

    In January 2014, the Governor’s Office identified groundwater management as one of ten key action steps in its California Water Action Plan. SGMA, signed into law months later, follows up on that action, giving local agencies the ability to manage their respective basins following statewide guidelines.

  • Will SGMA affect existing water and property rights?

    SGMA does not change existing groundwater rights. Groundwater rights will continue to be subject to regulation under Article 10, Section 2, of the California Constitution.

  • Is the State trying to take over control of groundwater?

    SGMA provides a framework for the improved management of groundwater supplies by local authorities. In fact, it specifically limits state intervention provided that local agencies develop and implement groundwater sustainability plans as required by the legislation. Under SGMA, local agencies now have tools and authorities some agencies previously lacked to manage for sustainability.

    Under a limited set of circumstances, the State Water Board may step in to help protect local groundwater resources. The process of State Water Board intervention is sometimes referred to as the State Backstop or State Intervention, and only occurs if local efforts to form a GSA or prepare a viable GSP are not successful.

    If local agencies fail to form a GSA by July 1, 2017, local groundwater users must begin reporting groundwater use to the State Water Board. State Intervention requirements then remain in place until local efforts are able to sustainably manage groundwater resources.


  • What is a Groundwater Sustainability Agency (GSA)?

    A Groundwater Sustainability Agency is one or more local governmental agencies that implement the provisions of SGMA. A local agency is defined as one that has water supply, water management or land management authority. GSAs assess the conditions of their local basins, adopt locally-based sustainable management plans to create drought resiliency, and improve coordination between land use and groundwater planning.

  • When will the GSAs be formed?

    All Groundwater Sustainability Agencies must be formed by June 2017.

  • What costs will be associated with forming and administering a GSA?

    Forming a GSA, then developing and implementing a Groundwater Sustainability Plan (GSP), will require both start-up and ongoing costs. As part of the GSA formation, the agencies will determine how to share costs for developing and implementing the GSP. GSAs may also take advantage of grants and other funding opportunities, such as Proposition 1 bond funds, to help create and implement a GSP.

  • What authority will GSAs have?

    Under SGMA, GSAs are empowered to:

    • Adopt rules, regulations, ordinances, and resolutions to implement the Act
    • Monitor compliance and enforcement
    • Require registration of groundwater extraction facilities (wells)
    • Require appropriate measurement devices and reporting of extractions
    • Investigate, appropriate, and acquire surface water rights, groundwater, and groundwater rights into the GSA;
    • Acquire or augment local water supplies to enhance the sustainability of the groundwater basin
    • Propose and collect fees
    • Adopt and fund a groundwater sustainability plan according to existing laws


    The GSA may use a number of management tools to achieve sustainability goals. The specific tools and methods the GSA will use to achieve sustainability will be determined in discussion with stakeholders and identified in the GSP.

    It is also important to note that SGMA requires local agencies to acknowledge Groundwater Sustainability Plans when a legislative body is adopting or substantially amending its General Plan. General Plans must accurately reflect the information in the Groundwater Sustainability Plan with regards to available water supplies.

  • Will stakeholders or the public have the opportunity to weigh in on the GSA formation process or the GSP?

    As public entities, the local agencies joining together to form a GSA will review the formation process and GSP adoption process as part of their regularly noticed public meetings. The agencies also anticipate conducting workshops and creating other opportunities for input.

  • What will be the Governance Structure for the proposed GSA? How will the agencies work together to run it?

    Each GSA must decide on the which governance structure to adopt. Common governance structures for GSAs include the use of a Memorandum of Agreement or a Joint Powers Authority.

  • If GSAs are locally controlled, what is the state’s role in this effort?

    The California Department of Water Resources (DWR) is the agency responsible for oversight of the GSAs and GSPs formation. DWR has a list of regulations, objectives and actions formulated to assist local agencies and GSAs with the preparation and implementation of GSPs. Under law, all regulations adopted by DWR only become effective only upon approval by the California Water Commission. Under a limited set of circumstances, the State Water Board may intervene if local efforts to form a GSA or prepare a viable GSP are not successful.

  • How will adjacent GSAs be handled?

    The regulations require that all GSAs coordinate with adjacent GSAs in a given basin. This coordination will occur through additional discussions with neighboring agencies as GSAs are formally developed, and the GSPs will describe how the adjacent GSAs will work together to achieve groundwater sustainability.

  • Does the GSA impact surface water?

    Not directly. However, this new groundwater management framework acknowledges the connectivity of surface water and groundwater, and that they are to be managed as “a single resource.”

  • What is a Groundwater Sustainability Plan (GSP)?

    A GSP is the plan of a GSA that provides for sustainably managed groundwater that meets the requirements of SGMA. GSAs in high and medium priority groundwater basins are required to submit a GSP to the California Department of Water Resources. The plan must outline how the GSA will implement, manage and measure specific actions for the health and viability of the basins. DWR will evaluate the GSP and provide the GSA with an assessment of the plan and any necessary recommendations every two years following its establishment.

  • When does a GSP have to be established?

    All GSPs must be completed and begun to be implemented by January 31, 2022.

  • What is the health of our current groundwater basins?

    Data collected over many years indicates the Delta-Mendota Subbasin is in good health. The current drought, however, has reduced some groundwater levels because lower precipitation has resulted in reduced recharge to the groundwater basin and some land subsidence.

Additional Information


Regional Groundwater Management

Technical Reports and Data

  • These items will be added as they become available.

Common Acronyms

DWR = California Department of Water Resources
GSA = Groundwater Sustainability Agency
GSP = Groundwater Sustainability Plan
JPA = Joint Powers Authority

MOA = Memorandum of Agreement
SGMA = Sustainable Groundwater Management Act
SWRCB = State Water Resources Control Board

Hot! Over 280 interface blocks, 140 demo pages and Variant Page Builder. Purchase Stack for $59 USD.

Let's get you started

Start building pages in your browser