The Sustainable Groundwater Management Act

In 2014, the California State Legislature adopted the historic Sustainable Groundwater Management Act (SGMA), which established a statewide framework to help protect groundwater resources. The information on this website will explain why SGMA is needed to ensure the protection of groundwater resources in the state for all Californians. The State Water Resources Control Board has developed frequently asked questions regarding groundwater and SGMA.

Because groundwater is not easily visible, it is often taken for granted, putting important drinking water and irrigation sources in jeopardy of going dry or being contaminated.

What is Groundwater?

Groundwater is found beneath the Earth's surface. Despite being difficult to visualize, groundwater makes up a significant portion of the Earth's water. When rain falls to the ground, some of it flows along the surface in streams, rivers, and lakes; some of it is used by plants; some evaporates and returns to the atmosphere; and some sinks into the ground as groundwater. Groundwater is stored in - and slowly moves through - layers of soil, sand, and rock (called aquifers).

Typically composed of gravel, sand, sandstone, or fractured rock, aquifers allow large underground reservoirs of water to accumulate. Layers of aquifers make up a groundwater basin. To learn more about groundwater, visit the USGS website.

Why Protect Groundwater?

Groundwater is one of California's greatest natural resources, making up a significant portion of the state’s water supply, and serving as a buffer against the impacts of drought and climate change. During a typical year, groundwater makes up approximately 40 percent of California’s total water supply and makes up to 60 percent during dry years. Groundwater is a major source of the state's drinking water supply; approximately 33 million Californians use groundwater for drinking or other household uses. Groundwater replenishes streams, creeks, rivers, and wetlands that support wildlife, and is used in agriculture to irrigate crops.

Overuse and excessive groundwater pumping can overdraft aquifers, emptying them faster than natural systems can recharge them. Overdraft can result in the lowering of groundwater levels causing land to subside, water supply wells to go dry, saltwater to intrude groundwater in coastal areas, and surface water supplies to diminish where interconnected to groundwater.

Overreliance on groundwater has caused these issues in in many of California’s groundwater basins. The Sustainable Groundwater Management Act (SGMA) was enacted in order to halt overdraft and bring basins into balanced levels of pumping and recharge. SGMA requires local agencies to adopt groundwater sustainability plans for high- and medium-priority groundwater basins. Under SGMA, basins must reach sustainability within 20 years of implementing their plans.

Ensuring sustainable management of groundwater is essential for California’s future water supply needs. Climate change and the threat of prolonged drought highlights the need for balancing water outflows and inflows, the "water budgets" in groundwater basins, and protecting or restoring groundwater quality and quantity throughout the state.

Sustainable Groundwater Management Act: Background and Development

In 2014, Governor Jerry Brown signed a three-bill legislative package, composed of AB 1739 (Dickinson), SB 1168 (Pavley), and SB 1319 (Pavley), collectively known as the Sustainable Groundwater Management Act (SGMA). SGMA is the first legislative act that California passed in order to achieve sustainable groundwater management (see the legislation with updates, effective January 1, 2019, for details). On May 16, 2016, the State Water Resources Control Board adopted a resolution to adopt an emergency regulation to implement SGMA. The Office of Administrative Law approved the final regulation on June 29, 2017.

SGMA established a new framework for how groundwater would be managed locally to achieve long-term sustainability. SGMA requires existing local agencies to form groundwater sustainability agencies (GSAs) in high- and medium-priority basins and to develop and implement groundwater sustainability plans (GSPs). GSAs are responsible for achieving long-term sustainable management of their groundwater basins and must achieve sustainable groundwater management within 20 years of implementing their GSPs.

These groundwater sustainability plans outline how groundwater will be sustainably used and managed without causing six undesirable results in the basins: significant and unreasonable declines in groundwater levels, reductions in groundwater storage, intrusion of seawater, degradation of water quality, subsidence of land, and depletions of interconnected surface waters. These are often referred to as the sustainability indicators. These GSPs will address overuse and excessive groundwater pumping, causing overdraft in the basins, to achieve balanced levels of groundwater to reach long-term sustainability. For those groundwater basins experiencing the most severe overdraft, known as the critically over-drafted basins, basins must achieve groundwater sustainability by 2040. For the remaining high- and medium-priority basins, 2042 is the sustainability deadline. See the Groundwater Legislature Timeline for more details.

In his signing statement, Governor Jerry Brown emphasized that "groundwater management in California is best accomplished locally."

Agencies Implementing SGMA

Local agencies are responsible for the sustainable management of their groundwater basins; however, state agencies are responsible for ensuring local groundwater management achieves SGMA's goals. The California Department of Water Resources (DWR), which is a state department in the California Natural Resources Agency and the State Water Resources Control Board (State Water Board), which is an independent board within the California Environmental Protection Agency are the two lead state agencies implementing SGMA.

Local Agencies

A GSA can be formed by a single local agency or a combination of local agencies in their basins to manage groundwater sustainably at the local level. Local agencies may include water districts, counties, irrigation districts, cities, and other local government entities. GSAs are responsible for developing and implementing GSPs that detail how groundwater will be sustainably managed and used.

California Department of Water Resources (DWR)

DWR is the primary technical assistance and oversight agency responsible for assessing and evaluating the GSPs for compliance with SGMA. DWR conducts these assessments at least every five years. The agency provides ongoing assistance to local agencies through Best Management Practices and guidance documents to assist GSAs in developing GSPs; through assistance and engagement, including facilitation support and written translation; by providing access to a variety of data and tools including data libraries and dataset viewers; and providing financial assistance through their Sustainable Groundwater Management Grant Program.

State Water Resources Control Board (State Water Board)

The State Water Board acts as the state “backstop” and will temporarily intervene in the management of a groundwater basin when groundwater sustainability plans (GSPs) in a basin fail. The State Water Board receives referrals from DWR for those GSAs whose plans are not compliant with SGMA. The State Water Board steps in to temporarily intervene in managing the basin in a process called "state intervention". The State Water Board works with the GSAs to resolve failures and end state intervention. GSAs then implement their plans to sustainably manage their basins at the local level. For additional tools and resources, visit More Information and Resources.

Contact Us

If you have questions, please contact us at 916-322-6508 or email at

Language Access Services

The State Water Board provides interpretation and translation services in any language at no cost to you.

  • Language interpretation for public meetings, workshops, and meetings with Water Board staff.
  • Written translation of documents including comment letters, fact sheets, and more.

To request these services, please complete the Language Access Form by clicking on the "Request Language Services" button below.

The form is available in English, Español (Spanish), Tagalog, 中文 (Simplified Chinese), 한국인 (Korean), Tiếng Việt (Vietnamese), ਪੰਜਾਬੀ (Punjabi).