Napa Valley’s wine industry, already under financial pressure, is facing another cost as county leaders move to comply with California’s groundwater sustainability requirements.

Under proposed fees for the 2026-27 fiscal year, even grape growers who do not pump groundwater would be charged $17.53 for every planted acre, the Napa Valley Register reported.

Growers who rely on groundwater for irrigation would pay an additional $26.91 per acre, bringing their total fee to $44.44 per acre.

County officials say the base fee is justified because all growers, including those who dry-farm or use surface water or recycled water, still benefit from the availability of groundwater in the region, according to the outlet.

Revenue from the charges would support the Napa County Groundwater Sustainability Agency, which is tasked under state law with meeting sustainability targets for the aquifer stretching beneath the valley from Calistoga to south of Napa.

Although the proposed rates are less than half of the maximum amounts some in the industry initially feared, wine leaders say the timing is especially painful for wineries and growers already navigating a tough business climate.

“To have this fee come now is very difficult for our members and our industry to weather,” Napa Valley Vintners’ Michelle Novi told supervisors in June.

Napa County had been using roughly $2 million a year from its general fund to support the groundwater agency, but that contribution has been reduced to $500,000 for the current fiscal year.

The rest of the agency’s operating budget will be covered through the new fees and its savings.

Rural homeowners and businesses with wells will also be charged $28.17 per parcel, while public water systems face a $58.47-per-acre-foot fee, per the Register.

Supervisors agreed in June to dip into agency savings to soften the first-year blow after hearing the industry’s concerns.

The board could approve the new rates Tuesday, with groundwater users ultimately seeing the charges appear on their property tax bills.