California’s Sustainable Groundwater Management Act, known as SGMA, is a 2014 state law that requires local agencies in medium- and high-priority groundwater basins to form management bodies, write sustainability plans, and bring their basins into long-term balance within 20 years.1Department of Water Resources. Sustainable Groundwater Management Act (SGMA) For well owners, the practical consequence is that pumping can now be measured, limited, and charged for by a local agency called a Groundwater Sustainability Agency, with the state taking over if local management fails. The law passed as a three-bill package (AB 1739, SB 1168, and SB 1319) and applies to 94 basins statewide, with the tightest obligations on 21 basins the state has identified as critically overdrafted.2Department of Water Resources. Basin Prioritization
Which Basins SGMA Covers
SGMA does not reach every groundwater basin in California. The Department of Water Resources ranks basins by priority using factors like population, number of wells, irrigated acreage, reliance on groundwater, and documented problems such as overdraft and subsidence.2Department of Water Resources. Basin Prioritization Only medium- and high-priority basins must form a Groundwater Sustainability Agency and write a plan. Low- and very-low-priority basins are exempt from those mandates, though they can opt in.
Within the high-priority tier, 21 basins carry the additional label of critically overdrafted, meaning they have been pumped beyond their ability to recharge over a sustained period. Those basins faced earlier deadlines and have drawn the most state scrutiny.
Who Manages Groundwater Locally
SGMA is built around the Groundwater Sustainability Agency, or GSA. Any local agency, or combination of them, overlying a basin can elect to become the GSA.3California Legislative Information. California Code Water Code WAT 10723 – Groundwater Sustainability Agency In practice the players are counties, irrigation districts, water districts, and municipal water departments, sometimes acting alone and often joining together so one basin is covered end to end. The GSA has to consider the interests of every type of user above it, from large irrigators to domestic well owners to disadvantaged communities and environmental uses.4California Legislative Information. California Code Water Code 10723.2
The design is local control with real regulatory authority behind it. The people closest to the water make the decisions, but if they cannot deliver, the state takes over.
What a GSA Can Require of Well Owners
Meters and Reporting
A GSA can require every well within its boundaries to have a water-measuring device. The cost of buying and installing the meter is on the well owner or operator, and the GSA sets the calibration schedule. Owners can also be required to file annual statements reporting total extraction in acre-feet for the previous water year.5California Legislative Information. California Code Water Code 10725.8
Extraction Limits and Well Spacing
Under Water Code Section 10726.4, a GSA may limit, suspend, or allocate extractions from individual wells or across a basin. It can impose spacing rules on new wells to protect existing ones, require pumpers to rotate, and authorize temporary or permanent transfers of extraction allocations, effectively setting up a tradeable system for groundwater within its boundaries.6California Legislative Information. California Code Water Code 10726.4
An extraction limit set by a GSA is a management tool, not a court ruling on anyone’s underlying water rights. That matters for landowners with historical claims to groundwater.
Fees
Once a sustainability plan is in place, a GSA can charge fees on extraction to fund administration, infrastructure, water supply projects, and other plan work. Fees can be flat, volumetric, or a combination. Extraction fees used to cover management costs must comply with Proposition 218, meaning the GSA has to go through Article XIII D’s notice and protest hearing procedure before adopting them. If a new fee is proposed, you have the right to protest it through that process.7California Legislative Information. California Code Water Code 10730.2
The Small-Well Exemption
SGMA creates a lighter path for small-scale domestic users. A “de minimis extractor” is someone who pumps two acre-feet or less per year for domestic purposes.8California Legislative Information. California Code Water Code 10721 Two acre-feet is roughly 650,000 gallons, which covers most single-family households on a private well.
De minimis extractors are exempt from the metering and annual reporting requirements that apply to larger pumpers.5California Legislative Information. California Code Water Code 10725.8 The exemption is not total. In a basin that goes under state intervention, the Board can require de minimis users to report and pay fees after a public hearing, and the GSA still accounts for small-well usage in its basin-wide water budget.
Deadlines and the 20-Year Clock
SGMA phased in on a staggered schedule. The 21 critically overdrafted basins had to submit their Groundwater Sustainability Plans by January 31, 2020. All other medium- and high-priority basins had until January 31, 2022.9California Legislative Information. California Code Water Code 10735.2
Submitting the plan starts a 20-year implementation clock. Critically overdrafted basins are aiming for sustainability by 2040, the rest by 2042. In between, GSAs file annual reports with the Department of Water Resources covering groundwater elevations, total extractions, surface water used for recharge, total water use, and changes in storage.10California Public Law. Water Code Section 10728 DWR also conducts a formal review at least every five years to judge progress toward the sustainability goal, and may recommend corrective action.11California Legislative Information. California Code Water Code 10733.8
Sustainability is defined by what the basin must avoid. The law lists six “undesirable results” that every plan has to set thresholds against: chronic lowering of groundwater levels, reduction in storage, seawater intrusion, degraded water quality, land subsidence, and depletion of connected surface water.8California Legislative Information. California Code Water Code 10721 Crossing those thresholds is what triggers trouble.
What Happens If Local Management Fails
When a GSA never forms, never files a plan, or files one DWR finds inadequate, the State Water Resources Control Board can designate the basin as probationary after a public hearing.9California Legislative Information. California Code Water Code 10735.2 For basins that are not critically overdrafted, intervention based on an inadequate plan also requires the Board to find long-term overdraft conditions.
Probation changes the picture for well owners. They have to report extractions directly to the state and pay fees. The current schedule includes a $300 annual base filing fee per well plus $20 per acre-foot pumped, rising to $35 per acre-foot if the Board adopts an interim plan. Late filers face a 25% monthly penalty. De minimis users, if required to report, pay $100 per well.12California State Water Resources Control Board. SGMA Reporting and Fees
If the local agency still cannot produce an acceptable plan, the Board can adopt and enforce its own interim plan, which stays in effect until the GSA shows a viable strategy. Enforcement can include orders restricting extraction or requiring physical improvements to water systems.13California State Water Resources Control Board. What is State Intervention The costs of state oversight land on the water users in that basin, which is meant to push local agencies to keep their own plans on track.
Basins Already Under Court Management
Some California basins were already managed by court decree before SGMA passed. In an adjudicated basin, a court has defined water rights, set extraction limits, and usually appointed a watermaster. These basins do not form GSAs or write GSPs, but they are not entirely outside SGMA. Under Water Code Section 10720.8, the watermaster or local agency must file annual reports with DWR by April 1 covering groundwater elevations, extractions, recharge, total use, storage changes, and the court-filed annual report, and must send DWR any amendments to the court’s final judgment within 90 days.14California Legislative Information. California Code Water Code WAT 10720.8
A non-critically-overdrafted basin may also skip a full GSP by submitting an alternative, such as an existing management plan, a court adjudication, or an analysis showing the basin has operated within its sustainable yield for at least 10 years. DWR reviews alternatives on the same five-year cycle as full plans.15Department of Water Resources. Alternatives to Groundwater Sustainability Plans
Where SGMA Stands
As of late 2025, 81 basins are operating under approved GSPs. Four high- or medium-priority basins have been found inadequate and referred to the State Water Resources Control Board for intervention, and three more high-priority basins with inadequate plans were returned to DWR for further review.16Department of Water Resources. Groundwater Sustainability Plans Central Valley subbasins including Tule, Kaweah, Kern County, and Delta-Mendota have been at the center of intervention proceedings, with some recently returned to local jurisdiction after resolving deficiencies.17California State Water Resources Control Board. Sustainable Groundwater Management Act (SGMA)
If you want to know how SGMA affects a specific property, the first step is to find out which basin the property sits in, its priority ranking, and which GSA covers it. From there the local plan, the fee schedule, and any reporting rules will tell you what the law requires of your well.