Permitting one winery at a time
Winery process water discharged to land was regulated case by case. A winery might hold general waste discharge requirements, individual requirements, or a conditional waiver, depending on its regional board and when it came up.
The Board's own count puts the result plainly. Of roughly 3,612 bonded wineries in California, an estimated 2,070 discharge process water to land in a way that would fall under a statewide order. As of a 2020 estimate, 589 were actually permitted. Not 589 of the 2,070. 589 of all of them.
So the majority of wineries that should have been regulated were not, and the ones that were had been handled inconsistently. That is the gap the Order exists to close, and it is why the Board reached for one instrument covering everyone rather than continuing to issue permits individually.
One order replaces all of it
The State Water Resources Control Board adopted Order WQ 2021-0002-DWQ. It covers winery process water discharged to land, from 10,000 up to 15,000,000 gallons a year, and sorts facilities into five categories by annual process water design flow. Below 10,000 gallons is exempt. Above 15,000,000 needs an individual permit rather than this one.
Requirements scale with the category. Tier 1 is a filing and an annual summary. Tier 4 carries groundwater monitoring wells and twice yearly reporting. That scaling is the whole design: the Board's stated intent was requirements commensurate with the complexity of the discharge.
The other 43 percent of wineries are outside it, generally because their process water goes to surface water under a different permit, or leaves the site by truck.
Why Napa is only feeling it now
Napa County has run its own winery wastewater programme since 1979, long before the statewide order existed. Napa wineries were not unregulated. They were regulated locally, by the County, under an arrangement that predated all of this.
When the statewide Order arrived, an interim agreement between Napa County and the San Francisco Bay Regional Water Board gave wineries already in the County programme a three year extension on their application date, running to January 20, 2027. That is why the rule has been in force since 2021 while Napa wineries carried on with the County. The extension is what is now expiring.
The Regional Board published its transition flyer in August 2026. For most Napa winery owners, that flyer is the first direct communication they have had about any of this, which is exactly why it feels sudden. It is not new. The local alternative to it is ending.
Why Sonoma's answer is a different answer
Sonoma sits under the North Coast Regional Water Board rather than San Francisco Bay, and the North Coast board runs its own programme for wine, beverage and food processors. There is a conditional waiver for smaller volumes, Order No. R1-2026-0001, and general waste discharge requirements above that, Order No. R1-2016-0002.
Sonoma County Vintners argued to legislators and Board staff that a single statewide approach was an unsustainable burden on small and mid sized North Coast wineries. A Sonoma County Vintners bulletin reports that the State Water Board approved the programme on August 4, 2026 and the waiver opened to new winery enrollments, and that wineries above the volume threshold may still qualify at a process water to wine ratio of 5 to 1 or less.
Both of those points come from a trade association bulletin rather than a Water Board document, and neither appears in the published order. They are worth knowing and worth confirming before anyone acts on them.