California’s Sustainable Groundwater Management Act, known as SGMA, is the state’s first comprehensive law regulating how much water can be pumped from underground basins. Signed by Governor Jerry Brown in 2014 as a package of three bills (AB 1739, SB 1168, and SB 1319), it requires local agencies in the state’s most stressed basins to bring groundwater use into long-term balance within 20 years of adopting a plan.1Department of Water Resources. Sustainable Groundwater Management Act (SGMA) For farms, water districts, and well owners sitting over a covered basin, that long-term goal has already turned into near-term obligations: registration, metering, extraction fees, and in some places hard caps on how much water you can pump each year.
Which Basins and Users Are Actually Covered
SGMA does not apply to every aquifer in California. The Department of Water Resources sorts each basin into one of four priority levels — high, medium, low, or very low — and only high- and medium-priority basins are required to be managed under the law.2California Legislative Information. California Water Code 10722.4 – Groundwater Basin Categorization Priority is driven by population above the basin, projected growth, the number of public and private wells, irrigated acreage, how much local users depend on groundwater, and documented problems like overdraft, subsidence, saltwater intrusion, and water quality issues.3California Legislative Information. California Water Code 10933 – Groundwater Basin Prioritization
If a basin is bumped from low or very low up to medium or high priority later, the local agencies get two years to form a management agency and five years to adopt a plan, rather than being held to the original statewide deadlines.2California Legislative Information. California Water Code 10722.4 – Groundwater Basin Categorization
Even within a covered basin, not every well owner faces the same requirements. SGMA defines a “de minimis extractor” as a person pumping two acre-feet or less per year for domestic use, a threshold that covers most households with a well, a home, and a modest yard. De minimis users are generally exempt from a GSA’s extraction reporting requirements. That exemption is not absolute: in a basin that lands in state probation, the State Water Resources Control Board can require de minimis users to report if their collective pumping is a significant share of basin extraction.4California State Water Resources Control Board. What is State Intervention?
SGMA also tells agencies to protect domestic drinking water wells, which tend to be shallower than agricultural or municipal wells. California treats domestic use as the highest priority of water use, grounded in the state’s Human Right to Water law (AB 685, 2012). When a GSA sets a minimum acceptable groundwater level, that floor is supposed to account for the shallowest wells in the basin, not just the deepest.
Who Runs SGMA Locally
SGMA puts day-to-day management in the hands of Groundwater Sustainability Agencies, or GSAs. Any local public agency with water supply, water management, or land use authority can become a GSA, alone or through a joint powers arrangement with other agencies.5Department of Water Resources. Groundwater Sustainability Agency (GSA) Frequently Asked Questions In practice, cities, counties, water districts, and irrigation districts fill the role. The deadline to form a GSA in a high- or medium-priority basin was June 30, 2017; any part of a covered basin left without a GSA after that date defaults to the county as the presumed GSA.6Department of Water Resources. Groundwater Sustainability Agencies
Once formed, a GSA can adopt rules, regulations, and ordinances to carry out the law.7California Legislative Information. California Water Code 10725.2 – Powers and Authorities A few of those powers reach straight into your operation if you pump groundwater:
- A GSA can require every well in its boundaries to register with the agency, giving it a full inventory of who is pumping and where.8California Legislative Information. California Water Code 10725.6 – Well Registration
- Once it has adopted a plan, a GSA can charge extraction fees on groundwater pumped from the basin to fund monitoring, administration, and plan implementation.9California Legislative Information. California Water Code 10730.2 – Groundwater Extraction Fees
- Many GSAs require pumpers to install flow meters, and some require telemetry equipment so the agency can see extraction in close to real time. Specific requirements vary by basin.
The sharpest tool a GSA has is the pumping allocation. The agency sets a basin-wide cap on how much groundwater can be withdrawn each year and then assigns individual allocations to users. Those allocations must respect existing California water rights, including the difference between overlying rights (landowners pumping for use on their own land) and appropriative rights (water taken for use elsewhere). The allocations do not change those underlying rights, but they do limit how much any single user can actually extract in a given year.
What Sustainability Means Under the Law
SGMA defines a sustainable basin by what should not be happening in it. Water Code Section 10721 lists six “undesirable results,” and a basin is considered sustainable only when none of them is occurring to a significant and unreasonable degree:10California Legislative Information. California Water Code 10721 – Definitions
- Chronic lowering of groundwater levels. Short-term drops during a drought do not count if extraction and recharge are managed so losses in dry years are offset in wet years.
- Significant and unreasonable reductions in the amount of water stored in the aquifer.
- Seawater intrusion, which particularly threatens coastal basins where pumping has pulled the water table below sea level.
- Degraded water quality, including the migration of contamination into usable zones.
- Land subsidence. In parts of the San Joaquin Valley, the ground has sunk by feet, damaging roads, canals, and pipelines.
- Depletion of surface water connected to the aquifer, which can dry up rivers and streams and harm downstream users.
Every GSA’s plan has to set measurable objectives for each of these six indicators and show how its actions will keep the basin out of trouble. The pumping caps, fees, and recharge projects a basin adopts are built back from these sustainability thresholds.
The Deadlines That Have Already Hit
SGMA runs on two tracks. Basins classified as critically overdrafted had to adopt a Groundwater Sustainability Plan by January 31, 2020. All other high- and medium-priority basins had until January 31, 2022.11California Legislative Information. California Water Code 10720.7 – GSP Submission Deadlines Both deadlines have passed, and the Department of Water Resources is working through its evaluations.
The Department has two years after a plan is submitted to determine whether it is approved, incomplete, or inadequate.12California Legislative Information. California Water Code 10733.4 – Department Evaluation An approval starts a 20-year clock to reach full sustainability: 2040 for basins that met the 2020 deadline, 2042 for those that met the 2022 deadline. In between, GSAs file annual reports by April 1 covering the prior water year and submit a more detailed evaluation at least every five years.13Department of Water Resources. Groundwater Sustainability Plans Those five-year checkpoints are why pumping cuts are already being phased in; the 20-year horizon does not translate into 20 years of business as usual.
What Happens When Local Management Fails
The enforcement backstop is the State Water Resources Control Board. After a public hearing, the Board can place a basin into probationary status. Triggers include failing to form a GSA by the 2017 deadline, failing to adopt a plan by the 2020 or 2022 deadline, or a Department finding that an adopted plan is inadequate or is not being implemented in a way likely to reach sustainability.14California Legislative Information. California Water Code 10735.2 – Probationary Basin Designation
Probation changes the day-to-day for every pumper in the basin. The State Water Board can require extractors to install meters and report annual pumping. Well owners pumping more than two acre-feet per year for domestic use generally fall within reporting, though the Board sets the specific scope for each basin through a public hearing.4California State Water Resources Control Board. What is State Intervention? Water Code Section 1529.5 directs the Board to recover its intervention costs through fees charged to well owners and landowners in the basin.
If problems are not corrected, the Board can escalate to an interim plan for the basin, which contains corrective actions, a timeline, and monitoring requirements adopted at a public hearing. The GSAs must be given at least one year to fix deficiencies before an interim plan takes effect.4California State Water Resources Control Board. What is State Intervention? A state-run plan tends to be more rigid and more costly for local users than a locally designed one.
Where Things Stand Now
As of the Department’s most recent determinations, 81 basins are operating under approved sustainability plans. Four high- and medium-priority basins have been found inadequate and are under the State Water Board’s jurisdiction for potential intervention, with three more high-priority basins returned to the Department for further review.13Department of Water Resources. Groundwater Sustainability Plans
The Tule Subbasin became the first basin formally designated as probationary after a State Water Board hearing in September 2024, putting all extractors there on notice that state-level reporting and fees would follow. More basins may face the same designation as the Department finishes its reviews and the five-year evaluations show whether local plans are actually improving conditions. For landowners and water users in a covered basin, SGMA is no longer a future problem. The allocations, fees, metering, and annual reports are here, and the next round of required reductions is already on the calendar.