TO: Napa County Planning Commission
FROM: Brian D. Bordona - Director of Planning, Building and Environmental Services
REPORT BY: Wendy Atkins, Planner II
SUBJECT: Ontrail Vineyards Micro-Winery Use Permit No. P25-00139
RECOMMENDATION
title
OZEGNA VINEYARDS, LLC C/O JIM FASSIO / ONTRAIL VINEYARDS MICRO-WINERY / USE PERMIT # P25-00139-UP
CEQA Status: Consideration and possible adoption of a revised Mitigated Negative Declaration and the Mitigation Monitoring and Reporting Program (MMRP). According to the proposed revised Mitigated Negative Declaration (State Clearing House No. 2026080629), the proposed project would not have any potentially significant environmental impacts after implementation of mitigation measures for Biological Resources. The project site is not included on a list of hazardous materials sites compiled pursuant to Government Code Section 65962.5.
Request: Approval of a Micro-Winery Use Permit to establish a new phased 5,000 gallons per year winery including the conversion of an existing barn to a winery, conversion of the existing farm labor office to winery tasting and accessory uses, construction of a new winery building and covered crush pad, and associated tours and tastings by appointment only.
The project is located on an approximately 13.33-acre site within the Agricultural Watershed (AW) zoning district with a General Plan land designation of Agricultural Resource (AR)/Agriculture, Watershed and Open Space (AWOS) at 3252 Silverado Trail, Napa, CA 94558; APN 039-610-003.
Staff Recommendation: Adopt the Initial Study/revised Mitigated Negative Declaration and the Mitigation Monitoring Report Program (MMRP) prepared for the project and approve Micro-Winery Use Permit No. P25-00139 as conditioned.
Staff Contact: Wendy Atkins, Planner II, (707) 259-8757; wendy.atkins@countyofnapa.org
Applicant Contact: Jim Fassio, 501 El Cerrito Ave, Hillsborough, CA 94010, (650) 333-3155; ozegna@comcast.net
Applicant Representative Contact: Covell Architects c/o Michell Covell, 1407 Main Street, Ste. 102, St. Helena, CA 94574. Phone: (707) 968-9280 or email: michelle@covellarchitects.com
body
EXECUTIVE SUMMARY
PROPOSED ACTIONS:
That the Planning Commission:
1. Adopt the revised Mitigated Negative Declaration and Mitigation Monitoring and Reporting Program based on the recommended Findings 1-7 in Attachment A;
2. Approve the Micro-Winery Use Permit Application No. P25-00139, based on recommended Findings 8-12 of Attachment A, and subject to the recommended Conditions of Approval in Attachment B.
Discussion:
The project was first heard during the July 22, 2026, Zoning Administrator (ZA) meeting. Prior to the hearing, the State of California Department of Fish and Wildlife (CDFW) submitted a comment letter which identified the project’s potential to impact Swainson’s hawk and recommended mitigation to reduce harm. Because potential impacts to Swainson’s hawk were not evaluated in the Negative Declaration, Staff recommended the ZA continue the hearing to a date certain to allow for preparation and circulation of a Mitigated Negative Declaration (MND).
The prior staff report and attachments are available via the following link:
https://napa.legistar.com/LegislationDetail.aspx?ID=7926136&GUID=86036C00-D57C-4975-9C12-DACDECFCB7B0&FullText=1
The video of the public hearing is available at the following link:
https://napa.granicus.com/player/clip/5837?view_id=3&redirect=true
The project was last heard during the September 30, 2026, ZA meeting. Prior to the meeting, Water Audit California (WAC) submitted a comment letter which requested the referral of the application to the Planning Commission and that the Mitigation Monitoring and Reporting Program be included as an attachment. WAC also identified erroneous information in the staff report, Recommended Findings, and Conditions of Approval and requested revisions related to groundwater monitoring, Water Availability Analysis, and Public Trust (see Attachment M - Public Comments). Staff has responded to WAC’s comments below under Public Comment.
The prior staff report and attachments are available via the following link:
https://napa.legistar.com/Calendar.aspx#docaccess-2393d1f223536c50385b1610b1a272ea
The video of the public hearing is available at the following link:
https://napa.granicus.com/player/clip/5866?view_id=3&redirect=true
The request is for a new 5,000 gallon per year Micro-Winery on an existing 13.33-acre parcel. The proposed winery project will be constructed in up to three phases. Phase 1 will include converting the existing 1,951 sq. ft. barn to production space and converting the existing 529 sq. ft. farm labor office to winery tasting and accessory use. Wine production would consist of fermentation only in barrels and bottles. Visitation shall not exceed 10 visitors per day and 70 visitors per week. No marketing events are proposed. The winery proposes to have one full-time and one part-time employee. Phase 2 will include converting the 1,951 sq. ft. barn to a non-winery use and constructing a new 4,103 sq. ft. winery building. Phase 3 will include the construction of a 730 sq. ft. covered crush pad and installation of either a production wastewater system or a hold and haul wastewater system.
After the September 30, 2026 ZA hearing, the plans (Attachment J - Graphics) were revised as follows: Sheets 2, 3, and 4 the statement “Phase 1 upgrade (E) Driveway to Meeting Minimum RSS Req for Micro Winery Driveway” was removed, Sheet 2 “Phase 1 (P) Fire Truck Turnaround” was revised to show as existing, and Sheet 2 “Phase 1: (P) Fire Truck staging Area (30’ x 10’)” was removed to show as existing. The above listed improvements were completed with Building Permit number BC24-00276-NEW.
ENVIRONMENTAL IMPACT
ENVIRONMENTAL DETERMINATION: ENVIRONMENTAL DETERMINATION: Consideration and possible adoption of a revised Mitigated Negative Declaration and MMRP. According to the proposed revised Mitigated Negative Declaration (State Clearing House No. 2026080629), the proposed project would not have any potentially significant environmental impacts after implementation of mitigation measures related to biological resources. The project site is not included on a list of hazardous materials sites compiled pursuant to Government Code Section 65962.5.
BACKGROUND AND DISCUSSION
Owner: Ozengna Vineyards, LLC, c/o Jim Fassio, ozegna@comcast.net, or (650) 333-3155
Applicant: Ozengna Vineyards, LLC, c/o Jim Fassio, ozegna@comcast.net, or (650) 333-3155
Zoning: Agricultural Watershed District (AW)
General Plan Designation: Agricultural Resource (AR)/Agriculture, Watershed and Open Space (AWOS)
Application Filed: May 20, 2025; Resubmittal Received: October 14, 2025; Resubmittal Received: November 24, 2025; Application Deemed Complete: December 22, 2025
Courtesy Notice: A Courtesy Notice was mailed to all property owners within a 1,000 foot radius and interested parties on November 20, 2025
Existing Development: 8.3 acres of vineyards, two residences, a 1,951 sq. ft. agricultural barn, and a 529 sq. ft. farm labor office, three wells, and a pump house
Proposed Winery Characteristics (based on full buildout):
Proposed Winery Building Size: 4,632 sq. ft.
Proposed Winery Development Area: 9,854 sq. ft.
Proposed Winery Coverage Area: 35,816 sq. ft. or 0.82 acres (maximum allowed: 25 percent or approximately 3.33 acres)
Proposed Production Capacity: 5,000 gallons
Proposed Accessory/Production Ratio: 39.3 percent (maximum allowed: 40 percent); 1,307 sq. ft. accessory and 3,326 sq. ft. production. Visitation activities occurring outdoors do not count towards the Accessory to Production Ratio.
Proposed Number of Employees: One (1) full-time and one (1) part-time
Proposed Visitation: Hosted daily, tours and tastings by appointment for a maximum of 10 guests per day Monday through Sunday, 70 persons per week during harvest and non-harvest seasons.
Proposed Days and Hours of Operation: Production hours between 9:00 a.m. and 5:00 p.m. Monday through Sunday and visitation hours between 9:00 a.m. and 6:00 p.m. Monday through Sunday.
Proposed Parking: Four (4) parking spaces [one (1) accessible, two (2) standard, and one (1) compact].
Setbacks:
Required road setbacks: 600 feet from the centerline of Silverado Trail.
Required property line setbacks: 20 feet front, 20 feet side, 20 feet rear.
Existing setbacks: The closest portion of the existing Farm Labor Office is approximately 534 linear feet from the centerline of Silverado Trail. Rear Setback 1,420 feet; Side setback 79 feet (north property line), 249 feet (south property line). The closet portion of the existing Barn is approximately 498 linear feet from the centerline of Silverado Trail. Rear Setback 1,234 feet; Side Setback 4.5 feet (north property line), 318 feet (south property line).
Proposed Setbacks: New Winery Building (Phase 2) would be located 1,271 linear feet from the centerline of Silverado Trail. Rear Setback 1,078 feet; Side Setback, 39 feet (north property line), 255 feet (south property line). The new covered crush pad (proposed in Phase 3) would be setback 657 linear feet from the centerline of Silverado Trail. Rear setback 1106 feet; Side setback 20 feet (north property line), 253 feet (south property line).
Adjacent General Plan Designation / Zoning / Land Use:
North: Agricultural Watershed (AW) / Agricultural Resource (AR) / Agriculture, Watershed and Open Space (AWOS)
South: Agricultural Watershed (AW) / Agricultural Resource (AR) / Agriculture, Watershed and Open Space (AWOS)
East: Agricultural Watershed (AW) / Agriculture, Watershed and Open Space (AWOS)
West: (across Silverado Trail) Agricultural Preserve (AP) /Agricultural Resource (AR)
Nearby Wineries located within one (1) mile of the project:
There are 14 existing wineries with this radius.
Parcel History:
The site is relatively level and contains minimal tree coverage. The property is served by three on-site wells for potable water and a septic system and leach field for on-site sewage disposal. The property is accessed via Silverado Trail. Planning Permit P22-00261-CLN determined the legal nonconformity for the existing barn and chicken coop recognizing setbacks from the north property line.
Code Compliance History:
There is one prior Code Enforcement Case associated with the project parcel related to re-framing the barn without a permit which was resolved with the Building Permit final for BR22-01929-ALT. There are no active
Code Enforcement cases for the property.
Discussion Points:
Setting
The project site is on a 13.33-acre parcel with access from Silverado Trail. The site is currently developed with two residences, an agricultural barn, a farm labor office, 8.3 net acres of commercial vineyards, three wells, and a pump house. A winery is located to the north of the site, to the east of the site there are vineyards, and to the south is a single-family residence. Across Silverado Trail to the west is a single family residence and vineyards. Hardman creek, a County identified significant stream, traverses the site approximately 700-feet east of the proposed winery development area. The site is accessed from a private driveway off of Silverado Trail.
Micro-Winery Use Permit Proposal
The purpose of the application is to establish a new Micro-Winery Use Permit for a 5,000 gallon per year winery with daily tours and tastings by appointment on a 13.33 acre parcel, for the Fassio family. The Micro-Winery Use Permit includes the following:
Phase 1 consists of the following (Note: Phase 1 is the initial phase and it shall be implemented prior to Phase 2 or Phase 3):
• Convert the existing 1,951 sq. ft. barn to production space for barrel fermentation and aging of up to 5,000 gallons of wine per year, with all crush activities occurring at an offsite facility, and utilizing an on-site self-contained mobile bottling service, which will be located south of the existing barn.
• Convert the existing 529 sq. ft. farm labor office to winery tasting and accessory uses.
• By appointment visitation, tours and tasting, and retail wine sales for up to 10 visitors per day, or 70 visitors per week.
• On-premises consumption of wine (Business and Professions Code Section 23358, 23390, and 23396.5) in a 2,500 sq. ft. area located on the outdoor patio of the tasting room.
• Hours of operation include seven days a week from 8 a.m. to 5 p.m., except during harvest, for production, and seven days a week from 9 a.m. to 6 p.m. for visitation.
• One (1) full-time and one (1) part-time employee (one employee is owner-operator who lives onsite).
• Installation of four (4) parking spaces [one (1) accessible, two (2) standard, and one (1) compact].
• Use of an existing domestic wastewater treatment system to serve the tasting room and winery. No winery process wastewater to be generated during Phase 1 of the winery facility; cleaning of equipment will occur offsite.
• Use of an existing groundwater well (Well #1).
Phase 2 consists of the following:
• Convert the 1,951 sq. ft. barn to a non-winery use or continue to use the barn as a winery building.
• Construct either a new 4,103 sq. ft. winery building or a 2,152 sq. ft winery building (provided the 1,951 sq. ft. barn continues use as a winery building).
• Installation of five each 5,000-gallon water storage tanks.
• Removal of 0.13 acres of existing vineyards to accommodate the new 4,103 sq. ft. winery production building.
• Construction of a fire truck turnaround in between the farm labor office and proposed new winery building.
Phase 3 consists of the following
• Construction of a 730 sq. ft. covered crush pad.
• On-site production and the installation of either a production wastewater system to accommodate on-site treatment or utilization of a hold and haul wastewater system.
Phases 2 and 3 may occur any time after completion of Phase 1 improvements.
Winery proposed production capacity is 5,000 gallons with all fermentation conducted on site and all wine produced from fruit grown on the property which has approximately 8.3 acres of vineyard. Barrell storage and aging will occur on site. During Phase 1 and Phase 2 crush activities would take place at an offsite facility. Upon completion of Phase 3 all fermentation and full crush operations would be conducted onsite.
Noise - Because the nearest residence is located approximately 276 feet from the proposed production building, a Noise Study was prepared by CIH Services, dated October 25, 2025, and an Addendum to the Noise Study was prepared on April 20, 2026. The Noise Studies reviewed the proposed project’s potential impacts to noise resources and provide the following conclusions:
Table 1
|
Phase |
Sound Level (DBA) at Neighboring Residence |
Table 8.16 |
Existing Conditions (dBA) |
|
Estimated Noise Levels at the Residence for each Phase using Most Probable Sound Power Levels (1) |
|
Phase 1 |
24 |
Night 45 dBA Day 50 dBA |
46-55 |
|
Phase 1 and 2 |
26 |
Night 45 dBA Day 50 dBA |
46-55 |
|
Phase 1, 2, 3 |
45 |
Night 45 dBA Day 50 dBA |
46-55 |
|
Estimated Noise Levels at the Residence for each Phase using Worst Case Sound Power Levels (1) |
|
Phase 1 |
34 |
Night 45 dBA Day 50 dBA |
|
|
Phase 1 and 2 |
34 |
Night 45 dBA Day 50 dBA |
46-55 |
|
Phase 1, 2, 3 |
50 |
Night 45 dBA Day 50 dBA |
46-55 |
Table Notes:
1 The sound power levels for various winery activities is discussed in the October 8, 2025, report.
Sound levels from the crush pad would be expected to be approximately 57 dBA at a 450-foot distance in an unobstructed environment. The crush pad is approximately 450 feet from the nearest residence. However, the existing 6-foot-tall wood fence will reduce sound attenuation by 6 to 10 dBA, and the existing vegetation along the property line will further reduce sound attenuation by 10 dBA, resulting in a sound level of between 37 and 41 dBA. Because the crush activities would not exceed 45 dBA due to the existing fencing and vegetation, the following condition has been included:
6.15 (e) Noise
To attenuate noise from the crush pad, the existing 6-foot-tall wood fence and the existing vegetation along the north property line shall be maintained in perpetuity.
To further demonstrate that noise attenuation will not exceed the allowable levels in Napa County Code Section, 8.16.070, staff has provided the following assessment.
As described in the Project Setting, above, land uses within vicinity of the project are rural residential properties, vineyards, and wineries. Of those land uses, the residential land use is considered the most sensitive to noise. Based on the standards in County Code section 8.16.070, noise levels, measured at the exterior of a residential structure or residential use on a portion of a larger property, may not exceed 50 dBA for more than half of any hour in the window of daytime hours (7:00 a.m. to 10:00 p.m.), and 45 dBA during the nighttime hours (10:00 p.m. to 7:00 a.m.).
Noise from winery operations is generally limited and intermittent, meaning the sound level can vary during the day and over the course of the year, depending on the activities at the winery. The primary noise-generating activities are wine tasting, mobile bottling services, Barrel Fermentation and Aging, Temperature Control, Tank Fermentation, Glycol Chiller, and Crush Pad Activities. The Napa County General Plan EIR indicates the average, or equivalent, sound level (Leq) for winery activities is 51dBA in the morning and 41dBA in the afternoon. Audibility of a new noise source and/or increase in noise levels within recognized acceptable limits are not usually considered to be significant noise impacts, but these concerns should be addressed and considered in the planning and environmental review processes.
Following the ‘inverse square law’ where noise attenuates by 6 dBA for every doubling of distance the sound levels from proposed uses are as follows:
• Wine tasting: sound levels from the outdoor tasting area would be expected to reduce to approximately 41 dBA at a 338-foot distance in an unobstructed environment. However, noise from the outdoor tasting area is expected to be further reduced by screening from the existing converted farm labor office. Therefore, outdoor wine tasting activities will not exceed the Rural Noise Levels allowed in Napa County Code Section 8.16.070 of 50 dBA.
• Mobile Bottling Services: sound levels from the mobile bottling services area would be expected to reduce to approximately 49 dBA at a 345-foot distance in an unobstructed environment. However, the placement of the mobile bottling vehicle south of the 27 foot tall wood barn will further reduce sound attenuation by 10 to 15 dBA , resulting in a sound level of between 30 to 34 dBA.
• Barrel Fermentation and Aging: sound levels from the outdoor tasting area would be expected to reduce to approximately 24 dBA at a 276-foot distance in an unobstructed environment. Barrel Fermentation and Aging activities will not exceed the Rural Noise Levels allowed in Napa County Code Section 8.16.070 of 50 dBA.
• Temperature Control: sound levels from the air conditioner equipment area would be expected to reduce to approximately 28 dBA at a 350-foot distance in an unobstructed environment. Barrel Fermentation and Aging activities will not exceed the Rural Noise Levels allowed in Napa County Code Section 8.16.070 of 50 dBA.
• Tank Fermentation: sound levels from the tank fermentation area would be expected to reduce to approximately 28 dBA at a 390-foot distance in an unobstructed environment. The equipment for the pump-overs will be located inside the building where the exterior noise levels will be further reduced by 15 to 30 dBA, resulting in a sound level of between 9 and 0 dBA. Tank Fermentation activities will not exceed the Rural Noise Levels allowed in Napa County Code Section 8.16.070 of 50 dBA.
• Glycol Chiller: sound levels from the Glycol Chiller would be expected to reduce to approximately 33 dBA at a 390-foot distance in an unobstructed environment. Glycol Chiller activities will not exceed the Rural Noise Levels allowed in Napa County Code Section 8.16.070 of 50 dBA.
Winery Setback from Silverado Trail - Section 18.104.230.A.1. states: “Wineries, or structures containing accessory uses allowed by Sections 18.16.030 (G) and (H) and 18.20.030 (I) and (J), shall meet a six hundred foot setback from the centerline of any state highway, Silverado Trail, or any arterial county road.” Section 18.104.230.C states “Legally constructed structures, existing prior to the enactment of the Winery Definition Ordinance (January 23, 1990), may be exempted from the setback provisions of subsection A of the section if it is found that use of this exemption will result in a more environmentally beneficial placement of the winery. The winery may not encompass or expand beyond the legally established footprint of the structure as it existed on the above stated date. An expansion of such structure beyond the footprint that legally existed on the above date shall comply with the setback provisions of subsection A of this section.”
Barn: The existing legal nonconforming 1,951 sq. ft. barn was constructed in 1906. It is located 498 linear feet from the centerline of Silverado Trail. The barn is proposed to be converted to production space for the winery. By using the existing barn as production space, no vineyards will require removal during Phase 1 and less carbon will be expelled by minimizing construction. Using the barn as a winery adds operational efficiency and supports the long-term sustainability of a small-scale wine production.
Legal Nonconformity Conditions of Continuance - Section 18.132.030
A legal nonconformity may continue notwithstanding any other provisions of this title and may be repaired, maintained, restored, rebuilt following destruction regardless of the extent of the destruction, rehabilitated, remodeled, redesigned or rearranged as long as all of the following conditions are observed:
A. The repair, maintenance, restoration, rebuilding, rehabilitation, remodeling, redesign or rearrangement does not enlarge, increase or extend the area of land occupied by the legal nonconformity or cubic content of any structures involved or the square footage of any structure other than a primary residence: does not relocate the legal nonconformity from the location it occupied on the date it first became a legal nonconformity; does not result in the construction of any additional structures, other than those otherwise permitted by the code, on the parcel or parcels occupied by the legal nonconformity; and does not increase the degree of the nonconformity as to volume of business or production, hours of operation, volume of traffic generated, or volume of waste produced or natural resources consumed. Notwithstanding the above, minor expansions of structures as determined by the director may be allowed for (i) accessory storage use added after November 1, 2008 and constituting no more than five hundred square feet of surface area cumulatively, and only for those legal nonconforming parcels in existence on July 1, 1993 which were used primarily for restaurant operations, (ii) uses solely to meet the minimum requirements of the Americans with Disabilities Act (ADA) requirements (such as adding access ramps or ADA compliant restroom facilities), and (iii) minor relocations of structures may occur where such movement decreases the nonconformity in questions (such as moving a structure further outside of a required setback).
The barn was restored in 2023 (Building Permit No. BR22-01929-ALT) consistent with the Certificate of the Extent of Legal Nonconformity (P22-00261-CLN). The 1906 barn required restoration and was repaired, rehabilitated, and renovated within its original footprint. It was in need of repair to remain standing. During restoration, repair and rehabilitation, the building was not substantially modified, it was not relocated, and there was no addition. The barn was an existing agricultural use, and is remaining an agricultural use. The work included repair and rehabilitating the existing walls, structural framing, siding, roofing, and waterproofing. Windows and doors were replaced in kind. The building is 119 years old, and per the County requirements the repair included bringing the barn up to code structurally. Only renovations needed to comply with current codes were done in the upgrades and repairs. Construction was completed within the existing barn footprint. The barn was not enlarged or increased in area. The proposed use of the barn as winery production will continue its use as an agricultural building. The storing of barrels and winery storage will reduce the volume of business, hours of operation, volume of traffic, and volume of waste or natural resources because the barn will be used as barrel storage. This overall reduces the uses in the barn as compared to the current existing uses of storage and workspace in conjunction with vineyard operations.
B. The legal nonconformity has not been determined by the director, the board of supervisors, the district attorney, or any other governmental official authorized by law to do so, to be conducted in such a manner as to constitute a public nuisance as defined in Penal Code Section 370 or any future amendment thereof.
The legal nonconformity has not been determined to be constructed in such a manner as to constitute a public nuisance.
C. A certificate of the present extent of the legal nonconformity is obtained in accordance with Section 18.132.050 prior to application for any building or other permits required in connection with the repair, maintenance, restoration, rebuilding, rehabilitation, remodeling, redesign or rearrangement of the legal nonconformity.
A certificate of the present extent of the legal nonconformity (P22-00261-CLN) was obtained in connection with the repair, maintenance, restoration, and rehabilitation of the barn.
D. The legal nonconformity has not lost its legal nonconforming status through abandonment as defined in Section 18.132.040.
The legal nonconformity has not lost its legal nonconforming status through abandonment. It is currently used for storage and workspace in conjunction with vineyard operations. The vineyard workers and the property owner use the barn to store tools, machinery, trucks, tractors, and other equipment essential for vineyard farming. Additional uses include bringing equipment in and out, as well as the maintenance, repair, and cleaning of tools and machinery.
Resolution No. 2010-48 - “To discourage property owners from constructing residences and barns with the express intent of converting them to wineries, the County does not generally support use permit proposals seeking to convert existing buildings to winery use if the buildings have been constructed or substantially modified within the last 5-7 years.” The project proposes converting the existing 529 sq. ft farm labor office to winery tasing and winery storage areas. The farm labor office was constructed in 2025 (BC24-00279-NEW). The building permit identified the structure as a Farm labor Management Building, not a residence or barn, and was not subject to the winery 600-foot winery road setback from Silverado Trail and is not subject to Resolution No. 2010-48. Utilizing the existing structure is environmentally beneficial because it does not involve new construction.
Groundwater Availability - CMP Civil Engineering & Land Surveying Inc. prepared a Water Availability Analysis (WAA), dated October 8, 2025, for the project to demonstrate that the proposed water use is not impacting groundwater in the area. The report includes Tier 1 calculations for the existing and proposed water uses.
Tier 1: The Tier 1 analysis considered existing uses onsite to include vineyard irrigation, residential water use, and farm labor office water use. The existing groundwater usage of the project parcel is estimated at 6.87 af/yr. The proposed project would result in a net decrease in groundwater use of 0.88 af/yr by updating the irrigation distribution system to increase distribution uniformity (DU).
Tier 2: The latest Interim Napa Well Permit Standards and WAA Requirements require an interference study for any proposed increase in groundwater use occurring from project wells within 500 feet of any off-site well or 1,500 feet from any spring. Due to the proposed decrease in groundwater use for an existing well, a well interference study is not required.
Tier 3: While a Tier 3 review is the County’s adopted method for complying with its duties under the Public Trust Doctrine, as discussed herein, the project will comply with the WAA Guidance document because the project will reduce existing groundwater use and reduce well pumping time. Well #1 is located 412 feet from Hardman creek, a County identified significant stream, and the overall water use for the parcel will be reduced by 0.88 af/yr. This will be accomplished through the revamping of the existing vineyards irrigation system and scheduling methodology. However, a stream interference study is not required if modifications to the location, construction, or operation of the project well are made to reduce any assumed harm relative to current conditions. In the case of this project, the project is proposing a reduction of 0.88 acre‐feet per year in overall groundwater use through revamping of the existing vineyard irrigation system and scheduling methodology. Through these changes in well operation, the project will reduce overall well pumping time, and will therefore reduce any assumed harm relative to current conditions. As part of the conditions of approval of this project, well meters will be installed and pumping logs will be maintained in order to verify the water use reduction. Groundwater use on the property will also be capped.
The project is proposing a reduction of 0.88 af/yr in overall groundwater use through revamping the existing vineyard irrigation system and scheduling methodology. Regulated Deficit Irrigation (RDI) practices will be implemented on the site. RDI will be achieved through careful monitoring of soil moisture conditions, evapotranspiration rates and distribution uniformity. The physical improvements expected to be installed onsite to facilitate RDI will be as follows: installation of an onsite weather station, installation of onsite soil moister sensors, installation of water meters on irrigation supply mains, and, installation of pressure compensating emitters. Within a given year and at the maximum expected flow rate of the project well, it is expected that the wells total proposed pump time will be decreased by 1,195 minutes compared to current conditions.
|
Source of Demand |
Existing (af/yr) |
Proposed (af/yr) |
Difference (af/yr) |
|
Residential (two) |
1.2 |
1.2 |
0 |
|
Agricultural |
5.64 |
4.65 |
-0.99 |
|
Winery |
0 |
0.14 |
+.14 |
|
Commercial (Farm Office Space) |
0.03 |
0 |
-0.03 |
|
Total |
6.87 |
5.99 |
-0.88 |
The project parcel currently contains three (3) wells and no new wells are proposed. The proposed winery will be served by the existing Well #1 (Project Well). The existing Well #1 will also continue to serve the vineyard. Well #2 and #3 will continue to provide water to the two residences. The project site and all three wells are within the GSA boundary and the Northeast Napa Management Area. Napa County’s WAA guidelines allocate 0.3 AFY of water per acre of land within the GSA; therefore, the 13.33 acres of project parcel with the GSA has an estimated groundwater recharge of 3.99 af/yr.
Currently, Well #1 is estimated to draw 5.99 af/yr, which is higher than the parcel’s annual rate of recharge of 3.99 af/yr, as calculated using the County’s Interim Well Standards. The proposed project with the updated irrigation distribution system and advanced irrigation scheduling techniques, would decrease groundwater use by 0.88 af/yr. A condition of approval 6.15(b) would be imposed to install a well flow meter on Wells #1, #2, and #3 to cap groundwater use at 5.99 af/yr.
Wastewater System - A Wastewater Feasibility Report, dated November 24, 2025, was prepared by CMP Civil Engineering & Land Surveying Inc. Based on the Wastewater Feasibility Study analysis, the project site already has suitable domestic wastewater treatment system capable of treating the domestic wastewater needs of the proposed winery. Phases 1 and 2 of the winery will not need an onsite process wastewater treatment system. However, in Phase 3 of this project, the process wastewater generated by the winery will have the option of utilizing a hold and haul type system or installing an onsite process wastewater system that meets the requirements of the Statewide WDR. Should an onsite process wastewater system be installed, the site’s existing vineyard is substantially larger than the area required for the compliant land‐application of treated process wastewater. Based on this information, it is feasible to treat and dispose of the domestic and production wastewater associated with the proposed winery in accordance with County and State requirements.
Greenhouse Gas Emissions - On April 20, 2022, the Bay Area Air District (BAAD) adopted updated thresholds for determining the significance of individual projects’ greenhouse gas impacts under CEQA. Under the new thresholds, proposed land use projects may be analyzed for consistency with a qualified greenhouse gas (GHG) reduction strategy in the event one has been adopted. To date, Napa County has not adopted a qualified GHG reduction strategy pursuant to CEQA Guidelines section 15183.5. Absent an adopted strategy, BAAD recommends that a land use project include specified minimum design elements to ensure that the project is contributing its “fair share” toward achieving the state’s key climate goal of carbon neutrality by 2045. Napa County has not adopted a qualified GHG reduction strategy or an air quality plan, therefore projects will be evaluated per the BAAD recommended minimum design elements.
The project will be required, through Conditions of Approval, to meet relevant design standards identified by BAAD, including prohibiting the use of natural gas appliances or plumbing and compliance with the California Building Code Title 24 standards. Additionally, Conditions of Approval require implementation of the checked Voluntary Best Management Practices Measures submitted with the project application which include limiting the amount of grading and tree removal.
Public Comments - As of the date of this staff report, six public comments letters were received, one opposing the project, two in support, a CDFW letter dated July 16, 2026 (identifying potential impacts to Swainson’s hawk), and two letters from Water Audit California, dated July 21, 2026, and September 29, 2026.
Comments in the July 21, 2026, Water Audit California letter were addressed by circulating an Initial Study/Mitigated Negative Declaration addressing Swainson’s hawk mitigation and including in the Initial Study/Mitigated Negative Declaration an aerial image of the footprint and surrounding areas of the project site. The Water Availability Analysis, prepared by CMP Civil Engineering & Land Surveying Inc., dated October 8, 2025, did not address surface-water impacts because a stream interference study is not required if modifications to the location, construction, or operation of the project well are made to reduce any assumed harm relative to current conditions; therefore, a stream interference study is not required. The Groundwater Demand Management Program is included in Condition of Approval (COA) No. 6.15(b).
To address comments in the September 29, 2026, Water Audit California letter, the Mitigation Monitoring and Reporting Program is included as Attachment D. Revisions were made to the Recommended Findings to correct erroneous information. COA No. 6.12 was revised to reflect CDFW’s Mitigation Measure BIO-1 language. COA No. 6.15(b) was revised to include metering and monitoring of all three project wells. COA No. 4.9 is now marked “[Reserved]” and COA No. 6.15 was added as a project specific condition to ensure that the project reduces total groundwater extraction on the parcel by .88 af/yr. All reporting to Napa County is available to the public unless it is confidential. If a member of the public requests water usage reports they are provided. The permittee’s wells shall be included in the Napa County Groundwater Monitoring program if the County finds the wells suitable.
The Water Availability Analysis, prepared by CMP Civil Engineering & Land Surveying Inc., dated October 8, 2025, did not address surface-water impacts because a stream interference study is not required if modifications to the location, construction, or operation of the project well are made to reduce any assumed harm relative to current conditions. As explained above, a Groundwater Demand Management Program is included in COA No. 6.15(b).
The Initial Study/revised Mitigated Negative Declaration Mandatory Findings of Significance was revised to include the BIO-1 Mitigation Measure (shown in underline). CDFW is listed as the responsible agency for implementing the Mitigation Measure. CDFW’s letter dated July 16, 2026, has also been included in the list of COA Nos, 4.18(f) and 6.1(f). The Board of Supervisor’s approved Conditions of Approval template was used for this project.
In response to WAC’s Items 5 and 6, the Engineering division provided the following comments:
Item #5
The commenter is incorrect that Tier 2 and 3 are not evaluated in the WAA. Additionally, the WAA provided is consistent with the Board adopted guidance document which states that estimated values may be used in the absence of metered data. The commenter is incorrect that the existing-use calculation doesn’t account for extractions from Well #2 and Well #3 (WAA, p. 3). There is no specific requirement to include Well Completion Reports (WCRs) within the WAA, these are publicly available documents and can be found with the Department of Water Resources map application. The project well is located greater than 1500’ from the Napa River, approximately 1200’ from Soda Creek and 412’ from Hardman Creek. There are no unnamed significant streams within 1500’ of the project well. The error of the date on the Engineering Division memorandum has been corrected.
Item #6
The County recognizes that the public trust doctrine imposes a duty independent of CEQA, and the project’s potential to impact public trust resources has been considered. The project does not rely on a “no net increase” standard. As conditioned, it will reduce groundwater extraction on the parcel from existing levels and will be required to meter, monitor, and report all groundwater extraction on the parcel.
Decision-making Options:
As noted in the introductory paragraphs of this report, staff recommends that the Planning Commission approve the project as proposed, subject to the findings and conditions of approval in Attachments A and B, respectively. However, staff has provided the following options for consideration by the Planning Commission.
Option 1: Approve the Project as Proposed (Staff Recommendation)
Disposition: This option would result in the adoption of the revised Mitigated Negative Declaration and Mitigation Monitoring and Reporting Program, and approval of the project as proposed. Staff recommends this option as the request is consistent with the standards set forth by the AW zoning district, and the provisions of the Micro-Winery regulations and other provisions of the County Code.
Action Required - Follow the proposed action listed in the Executive Summary. If conditions of approval are to be amended, specify conditions to be amended at the time the motion is made.
Option 2: Modify the Applicant’s Proposal and Reduce Visitation
Should the Planning Commission determine that the intensity of the visitation should be reduced, the Planning Commission may take action to reduce the number of daily, weekly, or yearly visitors and/or reduce the hours of operation.
Action Required - Follow proposed actions listed in the Executive Summary and amend scope and project specific conditions of approval to reduce the maximum daily visitation. If significant revisions to the Conditions of Approval are required, the item may need to be continued to allow staff adequate time to prepare the revised conditions.
Option 3: Deny the Applicant’s Proposal:
In the event that the Planning Commission determines that the project does not, or cannot meet the required findings for grating the Use Permit, the Planning Commission should identify what aspects of the project are in conflict with the required findings. State Law requires the Planning Commission to adopt findings, based on the General Plan and County Code, setting forth why the proposed Use Permit is not being approved.
Action required - Motion to deny the project
Option 4: Continuance Option:
The Planning Commission may continue an item to a future hearing date at its own discretion.
SUPPORTING DOCUMENTS
A. Recommended Findings
B. Recommended Conditions of Approval and Final Agency Approval Memos
C. Initial Study/Revised Mitigated Negative Declaration
D. Mitigation Monitoring Reporting Program
E. Use Permit Application
F. Water Availability Analysis
G. Wastewater Feasibility Report
H. Stormwater Control Plan
I. Noise Study
J. Graphics
K. Public Comments
L. Public Comments Water Audit California July 21, 2026
M. Public Comments Water Audit California September 29, 2026