Napa Valley & Sonoma County Conjunctive Wine Labeling Laws: A Producer’s Compliance Guide

Last reviewed: October 20, 2026

Wineries producing single-vineyard and sub-appellation wines in Napa Valley and Sonoma County must satisfy two overlapping layers of wine labeling law before submitting a TTB Certificate of Label Approval (COLA): federal TTB appellation-of-origin standards under 27 CFR Part 4 and California’s strict conjunctive labeling statutes under the California Business and Professions Code.

Overlooking a mandatory conjunctive “Napa Valley” or “Sonoma County” designation on a sub-AVA wine label is one of the most expensive compliance errors a producer can make—often discovered only after labels are printed or when a COLA application is returned for correction by TTB.

1. Federal TTB Appellation, Varietal & Vintage Baselines (27 CFR Part 4)

Before applying California’s conjunctive labeling statutes, every wine label must satisfy federal TTB composition and sourcing rules verified against crush weight tags, cellar blending logs, and TTB Form 5120.17 records:

• American Viticultural Area (AVA) Appellation (27 CFR § 4.25): At least 85% of the wine must be derived from grapes grown within the named AVA, and the wine must be fully finished within the state (California).
• County or State Appellation: Under federal law, 75% is the baseline for a county or state appellation, except California state law requires 100% California-grown grapes for any wine claiming a California or California county/AVA appellation (Cal. Bus. & Prof. Code § 25239).
• Varietal (Grape Type) Designation (27 CFR § 4.23): At least 75% of the wine must be derived from the named grape variety (e.g., Cabernet Sauvignon, Pinot Noir, Chardonnay) grown in the labeled appellation.
• Vintage Date (27 CFR § 4.27): At least 95% of the wine must come from grapes harvested in the labeled calendar year when labeled with an AVA (or 85% when labeled with a county or state appellation).
• “Estate Bottled” (27 CFR § 4.26): 100% of the grapes must be grown on land owned or controlled by the bottling winery within the same AVA where the bonded winery premises are located, and the winery must crush, ferment, finish, age, and bottle the wine in a continuous process without leaving the premises.

2. Napa Valley Conjunctive Labeling Law (Cal. Bus. & Prof. Code § 25240)

California Business and Professions Code § 25240 requires that any wine bottled on or after January 1, 1990 that names an American Viticultural Area (AVA) located entirely within Napa County must also state the designation “Napa Valley” in conjunction with the sub-AVA name on the label.

• Covered Napa Sub-AVAs: Atlas Peak, Calistoga, Chiles Valley, Coombsville, Crystal Springs of Napa Valley, Diamond Mountain District, Howell Mountain, Los Carneros (if claiming a Napa-specific sub-designation), Mount Veeder, Oak Knoll District of Napa Valley, Oakville, Rutherford, Spring Mountain District, St. Helena, Stags Leap District, Wild Horse Valley (Napa portion), and Yountville.
• Placement & Legibility: Whenever one of these sub-AVAs appears as the appellation of origin, “Napa Valley” must appear in direct conjunction with the sub-AVA so consumers clearly recognize the wine originates in Napa Valley.
• Napa Name Protection (§ 25241): California law also prohibits using a brand name containing the word “Napa” (or any Napa sub-AVA) unless at least 85% of the grapes were grown in Napa County (subject only to narrow pre-July 7, 1986 grandfathering exceptions).

3. Sonoma County Conjunctive Labeling Law (Cal. Bus. & Prof. Code § 25246)

California Business and Professions Code § 25246 governs wines bottled on or after January 1, 2014 that bear the name of a sub-AVA located entirely within Sonoma County (or within the Sonoma County portion of a multi-county AVA when claiming Sonoma provenance). Any such wine must also display the designation “Sonoma County” on the label.

• Covered Sonoma Sub-AVAs: Alexander Valley, Bennett Valley, Chalk Hill, Dry Creek Valley, Fort Ross-Seaview, Fountain Grove District, Green Valley of Russian River Valley, Knights Valley, Moon Mountain District Sonoma County, Petaluma Gap (when wholly Sonoma-sourced or conjunction triggered), Pine Mountain-Cloverdale Peak, Rockpile, Russian River Valley, Sonoma Coast, Sonoma Mountain, Sonoma Valley, and West Sonoma Coast.
• Type-Size & Placement Rules Under § 25246: The “Sonoma County” designation must appear on the container in a type size at least as large as the federal mandatory minimum (at least 2 millimeters for containers larger than 187 mL, or 1 mm for 187 mL or smaller) and must be legible and conspicuous on the front or back label.

Pre-Press Label Audit & TTB COLA Support

Before sending label artwork to press or filing in TTB COLAs Online, our TTB COLA & Formula Application team performs a line-by-line audit of mandatory statements, sulfite and government warning formatting, ABV tolerances, and Napa Valley / Sonoma County conjunctive labeling rules. Contact Taylor Marchand at Gateway Compliance Napa to review your labels before printing.

This guide provides general educational information and is not legal advice. Confirm current federal TTB and California Business & Professions Code labeling requirements for your specific wine and label artwork.