TO: Napa County Planning Commission
FROM: Brian D. Bordona, Director of Planning, Building & Environmental Services
REPORT BY: Dana Morrison, Supervising Planner - (707) 253-4437
SUBJECT: Tesseron New Winery-Use Permit No. P22-00309-UP
RECOMMENDATION
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TESSERON NEW WINERY USE PERMIT APPLICATION NO. P22-00309-UP
CEQA STATUS: Consideration and possible adoption of a Mitigated Negative Declaration. According to the Mitigated Negative Declaration, the proposed project could have potentially significant environmental impacts to Biological Resources, however, various Mitigation Measures and Conditions of Approval have been incorporated to reduce potential impacts to a less than significant level. The MND was circulated for public comment during the initial Public Hearing notice and Notice of Intent to Adopt a MND, which ran from March 13th, 2025, through April 15th, 2025; State Clearinghouse Number 2025030568. 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 Use Permit to allow a new winery with an annual production capacity of 20,000 gallons per year with the following characteristics:
a. Construction of a new 14,729 square foot (sf) cut and cover Type I cave with a 2,750-sf covered crush pad, and a 348-sf covered mechanical equipment area with an enclosed trash/recycling area:
i. Included in the cave is a 3,645-sf fermentation dome room with a 32-foot-high ceiling;
ii. The caves and domes will be used for winemaking, fermentation, aging, barrel storage, bottling, case good storage; dry good storage, as well as shipping and receiving; the cave will also contain an office, lab and two restrooms.
iii. A retaining wall will be constructed uphill of the cave and will be 56 feet 6 inches in height.
b. Excavation of approximately 20,000 cubic yards of spoils associated with the cave and construction of structure pads, all of the spoils will be distributed within the subject parcel or neighboring parcels under the same ownership, with spoils specifically occurring on APN 027-060-020-000 at various locations but outside of all required stream and ephemeral setbacks;
c. Onsite parking for three (3) vehicles; one (1) handicapped, one (1) compact and one (1) standard;
d. Up to one (1) full-time employee, and three (3) part-time employees;
e. Installation of a 50,000-75,000-gallon Fire Protection Water Tank located on a parcel under the same ownership but within the jurisdiction of the County of Sonoma (this will require the submittal and approval of building permit from Sonoma);
f. Upgrades to the existing wastewater system - with winery wastewater being collected, treated, and stored to be reused for irrigation onsite;
g. Installation of a new onsite Septic System and identification of new reserve area;
h. Removal of 15 native tree species, with replanting and permanent preservation of 45 trees;
i. Use of an existing on-site spring, currently used for residential water use, that will become the water source for the winery while the residence will be served by an existing well; and
j. Improvements to the existing paved driveway from Wall Road to ensure it meets Napa County Road and Street Standards.
No Tours and Tastings, or Visitations are proposed or being requested under this Use Permit; nor are Marketing events proposed. The cave will be a Type I Cave. The proposed winery facility is predominantly stepped into the existing hillside and will consist of the cut and cover cave, along with the covered crush pad and mechanical equipment area.
The winery is proposed on a 43.26-acre parcel located at 1000 Wall Road, Napa, on Assessor’s Parcel Number APN 027-060-022-000. This parcel is part of a larger holding under the ownership of Tesseron Vineyards, which includes the primary parcel APN 027-060-022-000, as well as APNs: 027-060-020-000 (location of proposed soils disposal areas), 027-060-023-000 (location of existing vineyard), 027-060-024-000 (location of existing vineyard), 051-200-016-000 (parcel located in Sonoma County and location of proposed water storage tank) and 051-010-079-000 (parcel also located in Sonoma County no development or disturbance proposed).
STAFF RECOMMENDATION: Adopt the Mitigated Negative Declaration and approve the New Winery Use Permit (P22-00309), as conditioned.
STAFF CONTACT: Dana Morrison, Supervising Planner, (707) 253-4437 or dana.morrison@countyofnapa.org.
APPLICANT REPRESENTATIVE CONTACT: Jon M. Webb, New Albion California, (707) 290-6740 or jwebb@albionsurveys.com.
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EXECUTIVE SUMMARY
PROPOSED ACTIONS
That the Planning Commission:
1. Adopt the Mitigation, Monitoring and Reporting Plan, and Mitigated Negative Declaration based on Findings 1-7 in Attachment A; and
2. Approve the New Winery Use Permit No. P22-00309, based on recommended Findings 8-12 in Attachment A and subject to the Recommended Conditions of Approval (COA) in Attachment B.
Continuance:
The item was continued at the April 16th, 2025 hearing, as staff realized that the proposed driveway improvements utilized an exemption option that had been allowed under the former County Road and Street Standards (RSS); however, this exemption option was removed with the 2023 update to the RSS. While the Engineering and Fire Division COAs did specifically note that the road would need to be updated to current RSS standards it was unclear if any exceptions (road, conservation regulations, etc.) would be required to complete this aspect of the project. As such, the item was continued so the applicant could revise the civil plans and demonstrate that the project access road could be built to current standards without triggering additional exceptions or CEQA review. The applicant has since provided updated plans, which were reviewed by County staff, and it was confirmed that the road can be widened to current RSS standards without the need for any exception requests or additional CEQA review.
Request:
The proposed winery will be located on one parcel (Winery Parcel APN 027-060-022-000) within a larger holding containing five (5) other parcels (APNs: 027-060-020-000, 027-060-023-000, 027-060-024-000 in Napa County and APNs 051-200-016-000 and 051-010-079-000 in Sonoma County).
The primary Winery Parcel (APN 027-060-022-000), proposed to contain the winery is developed with the following: a main residence, a barn, a garage, a pool, a tennis court, a solar panel array, a well, one 12,000 gallon concrete water tank, one (1) spring, access roads, and ~2.01 acres of vineyard. The adjacent parcels within the holding under the same ownership contain the following:
• APN -020 (Napa County): contains primarily open space with an access road, solar panels and a well;
• APN -023 (Napa County): contains a primary residence, two detached garages, a barn, a pool, access roads, and ~5.74 acres of vineyard;
• APN -024 (Napa County): contains access roads and 6.03 acres of vineyard;
• APN -016 (Sonoma County): contains access roads and 5.37 acres of vineyard; and
• APN -079 (Sonoma County): contains solar panels but is primarily open space
(see Attachment E).
The Winery Parcel (Primary APN: 027-060-022-000) includes the following approved structures: a barn (B97-01608), water tank (Building Permit 52814), garage (B01-01494), and the primary house (B97-00142). Not located on the primary parcel but located within the Tesseron Vineyards holding parcel (027-060-023-000) contains an approved main dwelling and detached garage (Building Permit 53149 and 53150), a second detached garage and a barn (Building Permit 57340). The existing vineyards blocks are located on the primary parcel (027-060-022-000), as well as on APNs 027-060-023-000, 027-060-024-000, 051-200-016-000. A total of 21 acres were approved under Erosion Control Plan 90-48 (see Attachment I) and there are a total of 19.15 acres within the holding. No vineyards are proposed or required to be removed to implement the project.
Historically, water for the vineyard and residences within the holding were served by one of the existing on-site springs (see Attachment F). If approved, the vineyard and residence will have their water needs swapped to be served by one of the existing on-site wells. The new winery proposes to utilize the existing spring that formerly served the vineyard and residence to supply the winery operations. Process wastewater produced by the winery will also be used to irrigate on site landscaping and vineyard located within the holding.
Staff has reviewed the proposal and found it to be consistent with the Zoning Ordinance and applicable General Plan policies. Staff prepared a Mitigated Negative Declaration (see Attachment C) that evaluated the environmental impacts of the project and necessary Mitigation Measures (MMs) to ensure there is no significant impact to Biological Resources. With no significant environmental effects anticipated, as mitigated and conditioned, and with the project’s consistency with adopted County policies and regulations, staff believes that the necessary findings for the project can be made and recommends approval of the New Winery Use Permit request as proposed and subject to conditions.
ENVIRONMENTAL IMPACT
ENVIRONMENTAL DETERMINATION: Consideration and possible adoption of a Mitigated Negative Declaration (MND). According to the proposed Mitigated Negative Declaration, the proposed project would not have any potentially significant environmental impacts to Biological Resources as mitigated. The MND was published on the State Clearinghouse (No 2025030568) on 3/13/2025 and the review period ran through 4/15/2025. The project site is not included on a list of hazardous materials sites compiled pursuant to Government Code Section 65962.5
BACKGROUND AND DISCUSSION
PROJECT INFORMATION:
Owner: Tesseron Vineyards, c/o Alfred Tesseron, 1000 Wall Road, (707) 638-2399, mb@invinovertasllc.com.
General Plan Land Use Designation: Agricultural Resource (AR)
Zoning District: Agricultural Watershed (AW)
Application Submittal: September 1, 2022; Resubmittals Received: April 20, 2023; January 25, 2024; July 5, 2024, and Continuance Resubmittal: April 23, 2025
Application deemed complete: July 5, 2024, and Continuance Resubmittal Deemed Complete: June 12, 2025
Parcel Size: 43.26 acres (APN 027-060-022-000)
Existing Development: A main residence, a barn, a garage, a tennis court, a solar panel array, one well, one 12,000 gallon concrete water tank, one (1) spring, approximately 2.01 acres of vineyard, and ranch roads.
State Clearing Housing No. 2025030568
WINERY CHARACTERISTICS
Winery Development Area: 0.08 acres or 3,726 sf
Winery Coverage: 1.22 acres or 53,134 sf, approximately 2.8% of the property. Prior to the updated civil plans winery coverage was 0.96 acres or 41,872 sf, which is approximately 2.2% of the property. The required additional earth work to widen the access road to current NCRSS standards is in substantial conformance with what was reviewed in the IS/MND.
Cave Size: 14,729 sf cut and cover cave
Production Capacity: 20,000-gallons per year
Accessory/Production Ratio: 462 sf accessory/ 17,363 sf production - approximately 2.7%
Number of Employees: one (1) full-time, three (3) part-time.
Visitation: None proposed.
Marketing Program Proposed: None proposed.
Days of Operation Proposed: Monday through Sunday
Hours of Operation: 9:00 AM - 5:00 PM
Parking Spaces: three (3)
Required yard setbacks: 20 feet
Existing yard setbacks: All existing and proposed winery development exceeds 20 feet from the property lines.
Required Road setback: Not applicable as access road to the winery is a private driveway.
Adjacent General Plan Designation / Zoning / Land Use:
North: Land under jurisdiction of the County of Sonoma.
South: Agriculture, Watershed and Open Space (AWOS) General Plan designation, Agricultural Watershed (AW) zoning - South of the project site is a 23.00-acre property developed with a single-family residence.
East: Agriculture, Watershed and Open Space (AWOS) General Plan designation, Agricultural Watershed (AW) zoning - east of the project site are APNs 027-060-020, -023 and -024 (224.00 acres, 42.23 acres, and 298.36 acres, respectively) consisting predominantly of open space but with some vineyard development on -023 and -024 as well as a single-family residence and various accessory structures on -023.
West: Land under the jurisdiction of the County of Sonoma including two APNs under the ownership of Tesseron Vineyards (APNs 051-200-016-000 and 051-010-079-000). APN -016 contains existing vineyard and vineyard avenues and is the proposed location for the fire suppression water storage tank.
Nearby Wineries located within one mile of the project - There are no wineries approved or pending within one mile of the project (see Attachment K).
Code Compliance History: None. There are no open or pending code violations for the site. The County is not aware of any compliance issues on the property and no complaints have been filed.
DISCUSSION POINTS:
Winery Proposal - With this application, the applicant is seeking to develop a new 20,000 gallon per year winery. Primary access to the winery will be via a private driveway, accessed off Wall Road. The property is moderately sloped (±5-29% slope) with elevations on the property ranging from approximately 1,540 feet above mean sea level (msl) to approximately 1,840 feet above msl.
The proposed cave will house both production and accessory uses (with accessory uses consisting solely of a winery office, janitors’ closet, public hallway and the non-employee restroom). No tours, tastings or events are proposed or will be approved as part of this request. The winery will be a cut and cover Type 1 cave, and the roof will contain a dome, and only the skylight, located above the dome, will be visible while the rest of the structure will be covered with soil which will be reseeded with a native wildflower seed mix, and will eventually return to a natural, vegetated state with the added benefit of new pollinator habitat. Maximum height of the winery structure is 42 feet, though there will be a 56-foot 3 inch retaining wall located uphill of the proposed cave. The winery structures include areas for crush, fermentation, and barrel storage, as well as accessory areas such as winery offices and non-employee restrooms, a freestanding garbage disposal structure and a mechanical/storage area (see Attachments D and E).
Setbacks - The proposed project meets all applicable minimum setbacks. No variances are requested or required as part of the proposal.
Visitation/Marketing Program - No tours, tastings, visitation, or events are proposed as part of this project.
Traffic - No TIS was prepared for the project, however, a Trip Generation form was submitted as part of the application and it noted total daily trips for weekdays and weekends to be 11, which is well below the 110-trip threshold in the Governor’s Office of Planning and Research guidelines and the County’s TIS Guidelines and VMT screening criteria (see Attachment D). The Department of Public Works has reviewed the project and approved with no conditions. Per their workflow in the County Permit Management System on September 19, 2022 “Based on the trip generation worksheet provided along with the Use Permit Application, TIS report not warranted, left turn lane warrant analysis not warranted, no COA is applied”. The project would not conflict or be inconsistent with CEQA Guidelines section 15064.3, subdivision (b). Impacts would be less than significant.
Access/Parking - Access to the winery site will be provided by the existing driveway currently off Wall Road. Regarding road access, the project was submitted in 2022, and proposed road improvements were designed to meet the 2021 Road and Street Standards which allowed for an existing agricultural road with turnouts to be utilized. Both Engineering and Fire reviewed and recommended approval of the project in September and October 2022, respectively, and provided Conditions of Approval for the project. When finalizing the project for public hearing in April 2025 it was realized that the project, as Conditioned by the Engineering Division and Fire Divisions would need to improve the driveway access to current the 2023 Road and Street Standards, requiring a 22’ wide access road. As such, the project was continued at the April 16 Planning Commission hearing so the applicant could provide updated civil plans demonstrating the project could meet the current RSS standards. A revised civil plan set was provided by applicant demonstrating that road could be improved to the required 22’ width and that no RSS exception or exceptions to the Conservation Regulations are required. The updated plans were reviewed by both the Engineering Division and Fire Division and updated Condition of Approval Memos have been provided. The IS/MND had already analyzed the project assuming that current road and street standards would be met, and the applicant has demonstrated that this is achievable and will not require an exception, nor will the widening impact existing water courses. The revision does result in an additional 11,262 of disturbed area (winery coverage) or 2.8% of the parcel which is still less than county maximum allowance of 25% of the parcel. On-site parking is proposed for three (3) vehicles, consisting of one compact, one standard and one handicapped space.
Biology - The Project Area contains 7.2 acres of annual grassland, 1.3 acres of mixed oak woodland, 2.4 acres of disturbed or developed lands, and 0.1 acres of agricultural lands. There are no wetlands or drainages within the footprint of the proposed development area and soil dispersal areas; there are three existing culverted drainages that cross under the access road which will be expanded to accommodate the widened access driveway. The Project will not substantially interfere with native wildlife species, wildlife corridors, and or native wildlife nursery sites. The Project will not significantly contribute to habitat loss or habitat fragmentation. No special-status species were observed during the reconnaissance level survey - additional surveys will also be required as noted in Biological Resource Assessment (Attachment H) were included as Mitigation Measures (MMs) in the MND, the Mitigation, Monitoring and Reporting Plan (MMRP - Attachment J), and also noted in the Recommended Conditions of Approval (Attachment B). A total of nine (9) Biological MMs were included (seven (7) were originally noted in the MND and two (2) additional MMs have been added at the request of CDFW, see end of Attachment L - Public Comment and Attachment N - Notices, Division and Agency Memos, and Correspondence) to ensure less than significant impacts to special status plants (MM BIO-1 and MM BIO-2), to crotch bumble bee (MM BIO-3), to Swainson’s Hawk (MM BIO-4), nesting birds and raptors (MM BIO-5), to roosting bats (MM BIO-6), and northern spotted owl (MM-BIO 7). Additionally, a COA has been included to require the cave fill (cave roof) be reseeded with a native wildflower seed mix to help generate pollinator habitat, with the area being actively maintained (removal of noxious weed, invasives and non-native) and reseeded as needed. The project already includes reseeding of the soils dispersal area as part of the project. The California Department of Fish and Wildlife did have an opportunity to review the proposed project and provide comments on the MMs prior to circulation of the IS/MND, as well as during the official IS/MND 30-day comment and review period. They provided minor edits to the MMs and requested the inclusion of the additional Mitigation Measures noted below), which have also been included in the Recommended Conditions of Approval and in the MMRP (Attachment B and J).
CDFW Mitigation Measure - Streams and Riparian Areas: The owner shall implement the following conditions to minimize impacts to streams and riparian areas:
a. Prior to the commencement of Project activities, the Project shall conduct a thorough assessment for potential impacts to streams and riparian habitat including but not limited to impacts resulting trail clearing, earth moving, and vegetation removal. If impacts to the bed, bank, channel, or riparian area of the streams cannot be avoided, the Project shall notify CDFW for potential Project impacts to the streams. More information for the Notification process is available at https://wildlife.ca.gov/Conservation/Environmental-Review/LSA <https://urldefense.com/v3/__https:/wildlife.ca.gov/Conservation/Environmental-Review/LSA__;!!GJIbE8EFNbU!2F2wYAS83suKL6nZkATF8KHg-ncszHYVc-HwLN73M0hXZt9ibbEn4s87EZLBKjGmChMzzRqoBPoxzZqAfY28W6UvWTZKGw74ceaiubsKzPQ$>. The Project shall comply with all measures of the Streambed Alteration Agreement (SAA), if issued, and shall not commence activities with potential to impact the stream until the SAA process has been completed. Impacts to the streams and riparian habitat shall be mitigated by restoring riparian habitat at a minimum 3:1 mitigation to impact ratio in area and linear feet for permanent impacts, all temporary impact areas shall be restored, and trees shall be replaced at an appropriate ratio based on size and species, unless otherwise approved in writing by CDFW. An SAA, if issued, may include additional avoidance and minimize measures to protect fish and wildlife resources.
CDFW Mitigation Measure - Clara’s Milk Vetch: The owner/permittee shall implement the following measures to minimize impacts associated with Clara’s Milk Vetch:
a. The permittee shall conduct surveys for Clara’s Hunt’s milk-vetch. Per CDFWs comments the permittee shall have a Qualified Biologist conduct botanical surveys during the appropriate blooming period and conditions for Clara Hunt’s milk-vetch (Astragalus claranus) at the Project site, and adjacent to it where plants could be indirectly impacted, prior to the start of construction. Surveys shall be conducted following CDFW’s Protocol for Surveying and Evaluating Impacts to Special Status Native Plant Populations and Sensitive Natural Communities (https://wildlife.ca.gov/Conservation/Survey-Protocols#377281280-plants <https://urldefense.com/v3/__https:/wildlife.ca.gov/Conservation/Survey-Protocols*377281280-plants__;Iw!!GJIbE8EFNbU!zKSmXi1v4GUb7grGlUlZW2Uvg4ffjewdoCR-E7EcVyWMbxh1OcgT0MNxpL-VQOOdqlJ7uT9LwOLpSVSrny71CWQP$>) and include checking reference sites for target special-status plant species, unless otherwise approved in writing by CDFW. Survey reports shall be submitted to CDFW prior to the start of construction. If full avoidance of a State listed species is not possible, the Project shall consult with CDFW and seek to obtain an ITP prior to Project commencement.
The Project will result in temporary impacts to suitable habitat for special-status plants (bend-flowered fiddleneck, narrow-anthered brodiaea, congested-head hayfield tarweed, Jepson's leptosiphon, Cobb Mountain lupine, and Clara’s Milk Vetch), as well as Swainson’s hawk, common nesting birds and raptor, Pallid bat, Crotch bumble bee, and native trees. The 15 trees proposed for removal in the cave location will be replanted at a 3:1 ratio (45 trees replanted) on the subject parcel in the area noted on page C1 of the Civil and Architectural Plan (Attachment E). The Project has been designed to minimize permanent land conversion, and the Project will not significantly reduce habitat for local or regional special-status plants or animals as Mitigated and Conditioned.
Noise - The project would result in a temporary increase in noise levels during construction of the winery and related infrastructure. Construction activities would be limited to daylight hours using properly muffled vehicles. Noise generated during this time is not anticipated to be significant. As such, the project would not result in potentially significant temporary construction noise impacts or operational impacts. Since the nearest residence to the winery development area is approximately 1,200 feet to the south of the proposed winery development, there is a low potential for impacts related to construction noise to result in a significant impact. Further, construction activities would occur during the period of 7am-7pm on weekdays, during normal hours of human activity. All construction activities would be conducted in compliance with the Napa County Noise Ordinance (Napa County Code Chapter 8.16). The proposed project would not result in long-term significant construction noise impacts. Conditions of approval identified below would require construction activities to be limited to daylight hours, vehicles to be muffled, and backup alarms adjusted to the lowest allowable levels. Impacts would be less than significant.
Additional regulations contained within County Code Chapter 8.16 establish exterior noise criteria for various land uses in the County. As described earlier in the report, land uses that surround the proposed parcel are predominantly agricultural (vineyards) but also include rural residences; of these land uses, the residential uses are 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 decibels for more than half of any hour in the window of daytime hours (7:00 a.m. to 10:00 p.m.). Noise impacts of the proposed project would be considered bothersome and potentially significant if sound generated by it had the effect of exceeding the standards in County Code more than 50 percent of the time (i.e., more than 50 decibels for more than 30 minutes in an hour for a residential use). 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 equipment associated with wineries including refrigeration equipment, bottling equipment, barrel washing, de-stemmers and press activities occurring during the harvest crush season, delivery trucks, and other vehicles. 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. Winery operations would occur between 9:00 a.m. and 5:00 p.m. (excluding harvest). The nearest off-site residence to the proposed winery is approximately 1,200 feet to the south of the proposed winery. Any outdoor equipment would be subject to the following standard conditions requiring that any exterior winery equipment be enclosed or muffled and maintained so as not to create a noise disturbance (COAs 4.16 and 6.6, Attachment B). Under the proposed project, no events are proposed.
The project would not result in a substantial temporary or permanent increase in noise levels or produce excessive ground borne vibration levels during construction.no blasting is proposed. Project operations were found to comply with the applicable Napa County noise limits, and no substantial permanent increase in noise levels was identified. The nearest off-site residence to the proposed winery development is ~1,200 feet - construction noise will be temporary in nature and additionally, no tours, tastings or events are proposed as part of the winery request. The winery is located in a compatible noise environment and the proposed project would not expose people to excessive noise levels associated with air traffic.
Wastewater - A Wastewater Feasibility Report was prepared in August 2022 by Applied Civil Engineering (see Attachment G). The project would require the construction of a new or expanded wastewater treatment system, the project and Report was reviewed by the Environmental Health Department, and they provided a Memo detailing their recommended Conditions of Approval which is attached to the end of Recommended COAs and Agency Approval Memos (Attachment B). However, as proposed the winery process wastewater will be collected, treated, stored, and used to irrigate onsite pastures in accordance with the California State Water Resources Control Board Winery General Order and therefore will not impact the existing septic system. The existing parcel is serviced by a pressure distribution type septic system. According to permit records the parcel contains a system that was designed for a peak flow of 1,200 gallons per day (gpd) for a residence with 10 potential bedrooms (a Use Permit request that was approved but never implemented). The leach field consists of 1,157 lineal feet (lf) of leach line located on a hillside below the driveway. The plans for the system prepared by Bartelt Engineering, indicate there are 3 - 1,500-gallon septic tanks and a 1,500-gallon dosing sump tank prior to the pressure distribution leach field. The predicted Combined Peak Sanitary Wastewater Flow for the proposed winery’s operational characteristics and existing residence of 1,260 gpd is more than the design capacity of the existing wastewater disposal system (1,200 gpd). Therefore, to meet the extra 60 gpd capacity the existing system is proposed to be augmented by adding 5 feet to each of the existing 12 lines (60 lf total added resulting in 1,212 lf total). This will increase the capacity from 1,200 gpd to 1,272 gpd which will meet the needs of the proposed winery Use Permit and existing residential uses. An expanded reserve area consisting of 6,300 sf is proposed and as noted in the report is adequate to accommodate the expanded wastewater system.
With water and wastewater treatment facilities provided on-site, the proposed project requires no determination of service or will-serve letters from water or wastewater treatment service providers. The winery is proposed to include self-treating and self-retaining areas. Work areas of the proposed winery would be covered with a roof and plumbed to discharge runoff into the on-site wastewater treatment system, also with the intent to preserve stormwater quality. Grading for construction for the storm drain pipelines and wastewater treatment system improvements would occur concurrently with site grading associated with the winery construction, which would be subject to the dust suppression measures noted in the Mitigated Negative Declaration (see Attachment C, Section III - Air Quality).
Groundwater Availability - A Groundwater Water Availability Analysis, dated August 2022 (see Attachment F) with Addenda dated April 25, July 5, 2024 and April 1, 2025 was prepared by Provost & Pritchard Consulting Group and Applied Civil Engineering, to determine the estimated water use of the existing development, the proposed project and water availability, and to assess potential drawdown impacts to neighboring wells and springs. There are approximately 19.5 acres of vineyard located within the holdings which are dry farmed. The proposed project will utilize an existing spring to supply water to the winery. Currently the spring provides water to the two residences, pools, accessory structures, and landscaping for the entire holding. If approved, the winery will be served by the spring while the residential water use will be swapped to be served by the existing well (Well No. 2) located on parcel 027-060-020-000 where the soils dispersal area is proposed. The original August 2, 2022 WAA notes that either of two wells within the holding will be utilized to serve the existing residential water demands. However, the applicant has identified, and a Condition of Approval (COA) is being included to specifically require that, the residential water demands utilize the well located on parcel 027-060-020-000 (Well No. 2). This is due to the fact that the well located on this parcel is not within 500 feet of any neighboring wells, nor within 1500 feet of a significant stream or a neighboring spring being utilized for domestic or agricultural use. The well has a pumping rate of 20 gallons per minute which would be able to handle the domestic water demands for the parcel. The Domestic Well Use Condition of Approval will ensure that the well that will be used for domestic water use within the holding does not negatively impact off-site wells or springs. Another Condition of Approval has been included specifically noting that no well water or surface water rights shall be used for winery operations and that if any other source of water is proposed or used for winery production or operations, it may trigger a Use Permit Modification or additional CEQA review (Recommended COAs Attachment B).
• Condition of Approval- Domestic Well:
The residential water uses for the holding shall be met by utilizing the existing well located on APN 027-060-020-000, and not the well located 027-060-022-000.
• Condition of Approval - Winery Water:
No well water or surface water rights shall be used for winery operations. The only approved water source for the winery is the spring as identified and discussed in the Staff Report and in the Mitigated Negative Declaration. If any other source of water is proposed or used for winery production or operations, it may trigger a Use Permit Modification or additional CEQA review.
There are two neighboring parcels, under separate ownership, one at APN 027-550-011-000 which is served by an existing spring, and APN 027-550-005-000 which is served by an existing well. However, the off-site well and spring are more than 2,800 feet from the identified project well located on 027-060-020-000 which has been conditioned to serve as the water use for Tesseron holding residential uses.
The WAA April 1, 2025 addendum clarified that the vineyard irrigation use (the vineyard is dry farmed but during replants irrigation will be required during vine establishment) could be accommodated from Well No. 2. According to the original WAA the existing vineyards within the holding are watered via rainfall (dry farmed) with supplemental irrigation is provided from existing surface water rights but has only been utilized during new vine establishment. Staff has reviewed the existing water rights permit for the existing reservoir located on 027-060-020-000, and it notes that the parcel is permitted to divert 4.5 af/yr of water for stock watering, recreation, and fire protection, as well as domestic uses; with not more than 2.5 af/yr of the 4.5 af/yr allocation withdrawn for domestic use. The approved ECP is from the 1991, and, as such is not as detailed as more recently approved ECPs, and the water source is not clearly identified. Report(s) of Licensee from 2016-2024, yearly reports submitted by the water rights license holder to the State Water Resources Control Board (SWRCB), demonstrate that no surface water has been utilized for vineyard irrigation; supporting the applicant’s representations and the WAA statement that the vineyard is dry farmed. The 2010 Report of Licensee does indicate that surface water rights were utilized for vineyard irrigation when the vineyard was replanted; however, besides this one instance there is no indication or evidence that surface water rights have been utilized for vineyard irrigation for the past 14 years. The applicant/property owner is aware that replants are subject to Track II or Track I ECP replant process and that the source of water used for the vineyard will be evaluated at the time the applicant/property owner seeks to replant the vineyard. As noted earlier, the WAA April 1, 2025 Addendum did asses future replant water use at 0.4 AF/yr and found that Well No. 2 could support both the residential water demands and the new vine irrigation (as needed). The determination of whether use of surface water pursuant to a water rights permit is appropriate or allowed falls under the jurisdiction of the Water Board, not the County. The property owner and applicant are aware that future replants are subject to the ECP replant process.
The project spring, located at the southwestern end of the property, is currently used to provide domestic water supply to the on-site residences, and has been the primary water source for the residences for many years. The current and historical residential demands for the holding have been estimated to be 1.35 acre-feet/year. With project development, the residential water use will be shifted to Well No 2 (this is also a Condition of Approval) located on APN 027-060-020-000 and said well will also be utilized for temporary new vine irrigation use; the spring will be used solely for winery demands. The winery demands from the spring are estimated to be 0.5 acre-feet/year. Hence, future use will result in lower demands on the spring compared to existing (current spring demands = 1.35 AF/yr, future demands = 0.5 AF/yr. No efforts will be made to modify or enhance the spring to increase yield. Using water that naturally flows out of the spring cannot contribute to the additional depletion of the spring, reduce the spring yield, or have a significant impact on the aquifer. The spring has not been observed by Tesseron vineyard staff or property owners to flow off the estate parcels, or flow to any creek, river, wetland or other water body. As use of the spring (at a high demand) is the existing baseline condition, the proposed project with a more than 50% reduction in spring water demand should not have a significant impact on ground or surface water resource in the vicinity.
As noted above, the total water use for the winery includes employee uses, process water, and water for wine production, and is estimated to be 0.5 AF/yr. All the water will come from the spring located at the southern end of the property (see Attachment E and F). The WAA, prepared before the 10-year PRISM data became the standard used a Normal Year and Dry Year Rainfall of 33.1 inches and 8.7 inches, respectively. The 10-year prism data was provided from Applied Civil Engineering dated July 5, 2024, and updated with the April 1, 2025 addendum; the 10-year PRISM data varies across the entire holdings but averages approximately 35.5 inches per year. According to said addendum, the Normal Year estimate used in the WAA was conservative compared to the 10-year PRISM data. For the 607.85 acre holding, using the PRISM 35.5 inches per year the recharge, assuming 5% recharge per the WAA, the recharge is 89.0 AF/yr (compared to 84 AF/yr in the WAA for Normal Year and 22 AF/yr for Dry Year]. For the new residential well parcel (APN: 027-060-020-000) a future water demand of 1.75 AF/yr is anticipated, for domestic water use and new vine irrigation. The recharge for this 215.1 acre parcel exceeds the demand of 1.75 AF/yr. For the 43.26 acre winery parcel, using the PRISM 35.5 inches per year the recharge, assuming 5% recharge per the WAA April 1, 2025 Addendum, the recharge is 7.0 AF/yr (compared to 6.0 AF/yr in the WAA for Normal Year and 1.6 AF/yr for Dry Year). This demonstrates that just the recharge on the winery parcel (7.0 AF/yr) is more than 3 times the estimated demand for the new winery use (0.5 AF/yr). Additionally, the total demand for all of the existing and proposed uses within the holding (2.25 AF/yr) is almost 40 times the estimated demand. As such, there should be adequate water on-site to provide for both the existing and proposed water uses and impacts would be less than significant.
Grape Sourcing - The project site will have approximately 19.5 acres of vineyards once the winery is constructed. The winery operator, through the use permit application, has indicated that they intend to maintain compliance with the 75% Napa Valley grape source requirement; furthermore 100% of the estate grapes will be used for winery production. The recommended conditions of approval include a requirement for compliance with the 75% grape sourcing rule (COA No. 4.6 - Attachment B).
PUBLIC COMMENTS:
As of the release of this staff report (6/20/2025) 10 comments have been received regarding this proposed winery development project (Attachment L). One comment letter from CDFW, eight comments of support and one comment in opposition of the project.
DECISION MAKING OPTIONS:
As noted in the Executive Summary Section above, staff is recommending approval of the project with conditions of approval as described in Option 1 below. Decision making options also include a no project alternative.
Option 1 - Applicant's Proposal (Staff Recommendation)
Disposition - This option would result in approval of a new 20,000-gallon per year winery. Staff recommends this option as the request is consistent with the Zoning Ordinance, applicable General Plan policies, and other County regulations. Furthermore, the modification does not increase groundwater demand over existing levels. There will be no significant environmental impacts, as mitigated, due to the new winery development, as discussed in the Mitigated Negative Declaration.
Action Required - Follow the proposed action listed in Executive Summary. If conditions of approval are to be amended, specify conditions to be amended at time motion is made. This option has been analyzed for its environmental impacts, which were found to be less than significant.
Option 2 - Deny Proposed Project
Disposition - In the event the Commission determines that the project does not, or cannot meet the required findings for the granting of the Use Permit, Commissioners should identify what aspect or aspects of the project are in conflict with the required findings. State Law requires the Commission to adopt findings, based on the General Plan and County Code, setting forth why the proposed Use Permit request is not being approved.
Action Required - Commission would make a motion to deny the project.
Option 3 - Continuance Option
The Commission may continue an item to a future hearing date at its own discretion.
ATTACHMENTS:
• Recommended Findings (Attachment A)
• Recommended Conditions of Approval and Agency Approval Memos (Attachment B)
• Initial Study/Mitigated Negative Declaration (Attachment C)
• Project Narrative, Application Submittal, Application Signatures (Attachment D).
• Civil and Architectural Plan Sets (Attachment E)
• WAA and WAA Addendums (Attachment F)
• Wastewater Feasibility Study (Attachment G)
• Biological Resources Assessment (Attachment H).
• Northern Spotted Owl Assessment (Attachment H.1)
• Vegetation Retention Analysis (Attachment H.2)
• Approval Letter Erosion Control Plan 90-48 (Attachment I)
• Mitigation, Monitoring and Reporting Plan - MMRP (Attachment J)
• Winery Comparison Table (Attachment K)
• Public Comments (Attachment L)
• Graphics (Attachment M)
• Notices, Division and Agency Memos, and Correspondence (Attachment N)