The State Water Resources Control Board on Sept. 17 adopted a resolution to return the Kern County Subbasin to Department of Water Resources oversight after staff verifies that the subbasin’s amended 2025 Groundwater Sustainability Plans (GSPs) address three priority items identified by staff.

The action followed a daylong continuation of a probationary hearing on the subbasin under the Sustainable Groundwater Management Act (SGMA). State board staff and representatives of the subbasin’s 20 groundwater sustainability agencies (GSAs) presented technical revisions to the 2025 plans and described expanded monitoring networks, revised minimum thresholds, and new well‑mitigation programs. Derek Yurosick, chair of the Kern County Subbasin Coordination Committee, told the board: “We took to heart the direction given by the board at the February 20 probationary hearing. You asked for a series of revisions. We listened. We delivered.”

Why it matters: The Kern County Subbasin ranked as a critically overdrafted basin and in 2023 received an inadequate determination from the Department of Water Resources (DWR). A probationary designation by the State Water Board would have required the board to collect extraction data and could have led to an interim plan if local agencies did not correct deficiencies. Returning the subbasin to DWR oversight is a procedural step that lets DWR continue technical review while local GSAs focus on implementing the revised GSPs and mitigation measures.

What the board decided and why
Board staff presented a review of the 2025 draft GSPs and told the board they recommended return to DWR oversight if GSAs resolved three prioritized issues: (1) an adequate mitigation program for drinking water wells impacted by any constituent for which a minimum threshold is established in the GSPs (including 1,2,3‑trichloropropane, or 1,2,3‑TCP); (2) an adequate mitigation program for state small water system wells or domestic wells with more than four service connections; and (3) elimination of a May 2026 sunset provision in the Kern Non‑Districted Land Authority joint exercise of powers agreement. Staff reported that GSAs had removed the sunset provision and described new mitigation tracks for affected wells and a funding assistance proposal for state small systems.

Natalie Stork, director of the Office of Sustainable Groundwater Management at the State Water Board, led the staff presentation and described the board’s role in SGMA intervention and the conditions under which the board may adopt an interim plan.

The board voted to adopt the staff‑proposed draft resolution as amended in the meeting (including late revisions to language concerning 1,2,3‑TCP). The vote was unanimous: Board member Nicole Morgan, Vice Chair Doreen D’Adamo, Board member Laurel Firestone, Board member Sean Maguire, and Chair Esquivel voted “aye.” The resolution directs staff to review the final adopted 2025 GSPs to confirm that the three priority items were addressed; if confirmed, staff will send a letter to DWR returning the subbasin to DWR oversight for ongoing evaluation.

Key technical points presented
- Monitoring and thresholds: GSAs expanded the groundwater level monitoring network to about 187 representative wells and proposed adding monitoring wells to fill remaining data gaps. Minimum thresholds for some monitoring wells were raised to reduce subsidence risk. Staff recommended additional threshold adjustments in limited areas (notably five monitoring wells in Henry Miller Water District).

- Pumping and overdraft: Staff quantified large interannual variability in pumping: roughly 2.3 million acre‑feet pumped in the critically dry 2022 water year versus roughly 1.0 million acre‑feet in 2023 and 2024; staff reported an estimated average overdraft of about 344,000 acre‑feet per year (2015–2023), roughly 25% of the basin’s sustainable yield.

- Dry‑well mitigation and funding tracks: GSAs described a two‑track dry well mitigation program run in collaboration with Self Help Enterprises: a mitigation track (up to $90,000 per domestic well, including replacement and emergency supplies) and a technical assistance track (up to $50,000) for public supply wells. Staff asked that state small water system wells (domestic wells with more than four service connections) be put on a mitigation track with potential assistance up to $100,000; GSAs said they are developing a funding assistance track for those systems.

- Groundwater quality: The 2025 plans set minimum thresholds for six constituents of concern (arsenic, nitrate, nitrite, uranium, 1,2,3‑TCP and total dissolved solids) and a defined exceedance/investigation process. GSAs proposed a dedicated degraded‑water mitigation track and a 60‑day investigation by an independent qualified professional for any monitoring‑well exceedance; staff remained concerned about attribution of impacts where causes are mixed and the GSAs’ reliance on reverse osmosis for 1,2,3‑TCP.

- Subsidence: GSAs reported limited historical subsidence (up to 1–3 feet in some discrete areas from 2015–2023) and adopted a subsidence exceedance policy and action plan. Staff highlighted remaining questions about distinguishing GSA and non‑GSA causes (for example, oil and gas operations) and about identifying critical head thresholds for infrastructure impacts.

Public comment and community concerns
Community groups and residents provided panel testimony calling for stronger protections and more proactive mitigation for drinking water users, particularly disadvantaged communities. Advocates urged the board to prioritize the human right to water, to ensure timely notification and support for affected domestic wells, and to expand mitigation eligibility rather than waiting until wells exceed maximum contaminant levels (MCLs). Tribal leadership from the Tejon Indian Tribe (Chair Octavio Escobedo) urged the board not to designate probation and to return the basin to DWR oversight, citing ongoing agreements that support tribal water security.

Implementation and next steps
The adopted resolution tasks State Water Board staff with reviewing the GSAs’ final adopted 2025 GSPs to confirm the three priority issues are adequately addressed. If staff confirms that the mitigation programs, monitoring improvements, and governance changes are in place, the board will send a formal letter to DWR returning the Kern County Subbasin to DWR oversight. The GSAs commit to continued outreach, filling monitoring gaps, refining mitigation tracks for state small water systems, and coordinating with infrastructure operators (for example, Friant Water Authority) on subsidence impacts. The board will remain engaged during implementation and staff indicated they will track progress.

Quotes
“We took to heart the direction given by the board at the February 20 probationary hearing. You asked for a series of revisions. We listened. We delivered,” Derek Yurosick, chair of the Kern County Subbasin Coordination Committee, said in the subbasin presentation.

“This hearing is an important opportunity to hear from … groundwater sustainability agencies, other organizations and individuals before the board makes a decision,” Chair Esquivel said in opening remarks.

Ending
Board members and a broad group of local agencies and community representatives described the outcome as the next step in an iterative, multi‑year implementation effort. The adoption means the basin will proceed under DWR’s technical review rather than under an immediate State Water Board interim plan, but the board will require staff confirmation that the three prioritized items are fully implemented before the administrative handoff. Public and municipal stakeholders said they will continue to monitor implementation, with special focus on drinking‑water mitigation, monitoring network completion, subsidence attribution, and outreach to disadvantaged communities.