Napa County slashes initial groundwater sustainability fees by 55%, defers drain tile debate
Napa County, California · Meeting date: August 11, 2026 · Published: August 12, 2026
The Napa County Groundwater Sustainability Agency utilized $750,000 in reserve funds to ease the first-year burden of its new groundwater fee, though agricultural users continue to press for volumetric metering and discounts for subsurface drainage capture.
Key points
- The Board unanimously approved FY 2026-27 rates that are 55% below the maximums established in a December 2025 fee study.
- The public water system rate drops to $58.47 per acre-foot, and the combined agricultural rate falls to $44.44 per acre.
- The rate reduction is subsidized by a $750,000 contribution from the agency's fund balance to provide financial relief to the wine and agricultural industries.
- Growers requested that water captured by subsurface drain tiles be classified as an 'alternative supply' to qualify for lower base rates, but a legal memo classified it as percolating groundwater.
- The Board referred the drain tile classification and a potential transition to universal volumetric metering to its Technical Advisory Group for further review.
Full report
The Napa County Groundwater Sustainability Agency (NCGSA) Board of Directors unanimously approved a 55 percent reduction to its newly implemented Groundwater Sustainability Fee for Fiscal Year 2026-27 during its August 11 meeting.
The fee, originally adopted in December 2025 to fund the implementation of the Napa Valley Subbasin Groundwater Sustainability Plan, allocates regulatory costs across agricultural, self-supplied, and public water system users. To provide financial relief to the local agricultural sector, the Board leveraged $750,000 from the NCGSA fund balance to subsidize the first-year revenue requirement.
Under the temporarily reduced structure, the combined agricultural rate will fall from a maximum authorized $98.74 to $44.44 per planted acre. The public water system rate drops from $129.87 to $58.47 per acre-foot, and the flat rate for self-supplied residential parcels decreases from $62.58 to $28.17.
Natural Resources Conservation Manager Jamison Crosby noted that extensive outreach over the spring allowed users to claim lower base rates if they do not rely heavily on groundwater. The county approved 68 dry farming verifications and 75 claims for alternative water sources, such as surface water diversions or recycled water, exempting those acres from the groundwater-irrigated surcharge.
However, the county rejected requests from the wine industry to classify water captured via subsurface agricultural "drain tiles" as an alternative water source. Industry representatives argued that capturing this water reduces summer aquifer pumping and should be incentivized. A County Counsel legal memo clarified that, under California law, water intercepted by drain tiles is considered percolating groundwater, making it ineligible for the alternative supply discount.
During the hearing, several public commenters and Board members expressed a desire to eventually transition from the current acreage- and parcel-based model to a purely volumetric fee based on universal well metering. Chief Deputy County Counsel Thomas Zeleny cautioned that the current fee functions primarily as an administrative charge to fund the nascent agency's operations. He noted that a volumetric structure is difficult to implement until physical infrastructure or recharge projects are developed.
The Board authorized the reduced fees to be levied on the upcoming property tax roll and referred the drain tile classification and the potential transition to universal volumetric metering to its Technical Advisory Group for further evaluation.
This summary was generated by AI based on the source document and may contain errors.
Source: Board of Supervisors, Napa County