City
Town of Yountville
Town of Yountville ADU Ordinance
Summary
Local ADU ordinance establishing development standards for accessory dwelling units.
Full Text
Town of Yountville
ACCESSORY DWELLING UNITS
17.156.020 Definitions
"Attached accessory dwelling unit" means an accessory dwelling unit that is attached to the primary dwelling unit, not including a junior accessory dwelling unit.
"Detached accessory dwelling unit" means an accessory dwelling unit in a separate structure from the primary dwelling unit.
"Efficiency kitchen" means a cooking facility with a sink and refrigeration, a food preparation counter, and storage cabinets.
"Floor area" has the same meaning as defined in Section 17.100.020.
"Garage" has the same meaning as defined in Section 17.236.010.
“Historic property” means a property located within a historic district or a property listed on the State Historic Resources Inventory, as defined in Section 5020.1 of the Public Resources Code, or within a site that is designated or listed as a town or county landmark or historic property or district pursuant to a town or county ordinance.
"Junior accessory dwelling unit" or "JADU" means a residential dwelling unit that is no more than 500 square feet in size and contained entirely within an existing or proposed single-family structure. A junior accessory dwelling unit may include separate sanitation facilities, or may share sanitation facilities with the primary dwelling unit and have direct access to the primary dwelling unit. Junior accessory dwelling units are limited to one per residential lot zoned for single-family residences with a single-family residence built, or proposed to be built, on the lot.
“Living area” means the interior habitable area of a dwelling unit, including basements and attics, but does not include a garage or any accessory structure.
"Lot coverage" means the percentage of the total lot area that is occupied by buildings or structures that are roofed or otherwise covered or that are unroofed and have a finished floor
"Primary dwelling" or "primary residence" means an existing or proposed single-family or multifamily dwelling located on a lot in any of the following zones—RS (Single-Family Residential), RM (Mixed Residential), H (Old Town Historic), MPR (Master Planned Residential), and PD (Planned Development)—if the property's existing single-family dwelling is legal, whether conforming or nonconforming.
“Proposed dwelling” means a dwelling that is the subject of a permit application and that meets the requirements for permitting.
“Public transit” means a location, including, but not limited to, a bus stop or train station, where the public may access buses, trains, subways, and other forms of transportation that charge set fares, run on fixed routes, and are available to the public.
(Ord. 22-509 § 2; Ord. 25-532, 7/15/2025)
A. "Accessory dwelling unit" or "ADU"
The definitions in this section shall apply to this chapter only. Unless otherwise defined in this section, the definitions in Section 17.236.010 shall apply.
means an attached or a detached residential dwelling unit, which provides complete independent living facilities for one or more persons. An ADU shall not have direct access to the primary residence. It shall include permanent provisions for living, sleeping, eating, cooking, and sanitation on the same parcel the primary dwelling unit is situated. An accessory dwelling unit shall not be considered to exceed the allowable density for the lot upon which it is located, and shall be deemed to be a residential use that is consistent with the existing general plan and zoning designations for the lot. An accessory dwelling unit also includes the following:
1. An efficiency unit, as defined in Section 17958.1 of the Health and Safety Code; and
2. A manufactured home, as defined in Section 18007 of the Health and Safety Code
If the Planning Officer determines that an accessory dwelling unit or a junior accessory dwelling unit meets the following requirements, the Planning Officer shall approve the application for the unit. Unless specifically relating to one unit or the other, all accessory dwelling units and junior accessory dwelling units shall meet the following requirements:
17.156.030 Site and layout standards
When a permit application for an accessory dwelling unit is submitted with a permit application to create a new single-family dwelling or a new multifamily dwelling on the same lot, provided the accessory dwelling unit or the parcel satisfies any other criteria listed in this subsection.
(Ord. 22-509 § 2; Ord. 23-517 § 1; Ord. 25-532, 7/15/2025)
A. Zoning
1.
Pursuant to Section 17.12.010 (General Requirements for New Development and Land Uses) accessory dwelling units and junior accessory dwelling units are only permitted in the following zoning districts:
a.
A (Agriculture), RS (Single-Family Residential), RM (Mixed Residential), H (Old Town Historic), MPR (Master Planned Residential), and PD (Planned Development).
2.
Accessory dwelling units and junior accessory dwelling units are prohibited in the MHP (Mobile Home Park), PP (Parks and Playfields), PF (Public Facilities), PC (Primary Commercial), RSC (Residential-Scaled Commercial), OTC (Old Town Commercial), RC (Retained Commercial), and MU (Mixed Use Overlay) zones.
B.
Historic Properties. An accessory dwelling unit or a junior accessory dwelling unit proposed for an historic property shall be located in the rear half of the property.
C. Floor Area of ADUs
1.
The maximum size of the floor area of an accessory dwelling unit shall not exceed 850 square feet or, if the accessory dwelling unit provides more than one bedroom, 1,000 square feet.
2.
If an attached accessory dwelling unit is proposed on a lot containing an existing primary dwelling, the total floor area of the attached accessory dwelling unit shall not exceed 50% of the existing primary dwelling.
3.
Nothing in this chapter shall prohibit the development of an efficiency unit or an accessory dwelling unit that is at least 800 square feet, with four-foot side and rear yard setbacks, and constructed in compliance with all other local development standards.
D. Floor Area of JADUs
1.
The maximum size of the floor area of a junior accessory dwelling unit shall not exceed 500 square feet.
2.
The minimum size of the floor area of a junior accessory dwelling unit shall be greater than 220 square feet, pursuant to the International Building Code of the International Code Council Standards.
E. Lot Coverage
1. The maximum lot coverage shall be no greater than 60%
2.
The lot must contain an existing single-family detached dwelling unit and no other dwelling units. There shall be no more than one accessory dwelling unit and one junior accessory dwelling unit per lot with a single-family dwelling.
F.
Setbacks. The setback standards for accessory dwelling units are as follows:
1. Front yard setback—Consistent with applicable setback regulations in Division 2 of Title 17
2. Side yard setback—four feet
3. Rear yard setback—four feet
4.
There are no setback requirements for an existing living area or accessory structure, or a structure constructed in the same location and to the same dimensions as an existing structure, that is converted into an accessory dwelling unit or portion of an accessory dwelling unit.
5.
If an existing multifamily dwelling has a rear or side setback of less than four feet, the Town shall not require any modification of the existing multifamily dwelling as a condition of approving the application to construct an accessory dwelling unit that satisfies the requirements of this subparagraph.
G. Height Limits
1. Accessory dwelling units shall not exceed:
a.
16 feet in height measured to top of parapet or highest point of the roof for a detached accessory dwelling unit on a lot with an existing or proposed single-family or multifamily dwelling unit.
b.
18 feet in height measured to top of parapet or highest point of the roof for a detached accessory dwelling unit on a lot with an existing or proposed single-family or multifamily dwelling unit that is within one-half of one mile walking distance of a major transit stop or a high-quality transit corridor as defined in Section 21155 of the Public Resources Code. An additional two feet in height is allowed under this subsection to accommodate a roof pitch on the accessory dwelling unit that is aligned with the roof pitch of the primary dwelling unit.
c.
18 feet in height measured to top of parapet or highest point of the roof for a detached accessory dwelling unit on a lot with an existing or proposed multifamily, multistory dwelling.
d.
25 feet in height measured to top of parapet or highest point of the roof or the otherwise applicable height limitation under Title 17 that applies to the primary dwelling, whichever is lower, for an accessory dwelling unit that is attached to a primary dwelling.
e. Two stories in height in all cases
H. Parking
1.
A minimum of one screened off-street parking space shall be provided for each accessory dwelling unit. Surface parking may encroach up to 15 feet into the rear setback. The additional on-site parking space required for the accessory dwelling unit may be provided by tandem parking.
2.
If an existing garage, carport, or covered parking structure is to be demolished in conjunction with the construction of an accessory dwelling unit, the required off-street parking for the primary dwelling unit need not be replaced. Replacement parking spaces may be provided in any configuration on the lot, including, but not limited to, covered, uncovered, or tandem spaces, or by the use of mechanical automobile parking lifts.
3.
Notwithstanding any other provision of this code, no additional parking shall be required for an accessory dwelling unit if any of the following is true:
a. The unit is located within one-half of one mile walking distance of public transit;
b. The unit is located within an architecturally and historically significant historic district;
c. The unit is part of the proposed or existing primary residence or an existing accessory structure;
d. On-street permits are required but not offered to the occupant of the unit;
e. There is a car share vehicle located within one block of the unit; or
f.
Accessory dwelling units and junior accessory dwelling units are subject to the following development standards:
17.156.040 Development standards
(Ord. 22-509 § 2; Ord. 23-517 § 2; Ord. 25-532, 7/15/2025)
A. Facilities
1.
An accessory dwelling unit and a junior accessory dwelling unit shall have the following features located within the unit:
a. Independent heating controls, and cooling controls if air conditioning is provided
b.
Its own kitchen with sink and standard built-in or freestanding appliances, except that a junior accessory dwelling unit shall have an efficiency kitchen.
c.
Its own bathroom with toilet, sink, and tub or shower, except that a junior accessory dwelling unit may share these facilities with the primary dwelling unit, provided the junior accessory dwelling unit has a separate entrance from the main entrance to the primary dwelling unit, with an interior entry to the main living area of the primary dwelling unit.
d.
Indoor washer and dryer hookups, except that a junior accessory dwelling unit may share these facilities with the primary dwelling unit.
e.
Exterior access independent from the primary dwelling unit. Except for a junior accessory dwelling unit, there shall be no shared access with the primary dwelling unit.
B. Utilities
1.
A new or separate utility connection shall be required for all accessory dwelling units that are not described in paragraph 1 of subdivision (a) of Section 66323 of the California Government Code.
2.
A connection fee and capacity charge for utilities, including water and sewer service, shall be charged for such accessory dwelling units proportionate to the additional burden the unit places on the service(s) provided, based upon either its square feet or the number of its drainage fixture unit (DFU) values, as defined in the Uniform Plumbing Code adopted and published by the International Association of Plumbing and Mechanical Officials. This fee or charge shall not exceed the reasonable cost of providing this service.
3.
For purposes of providing service for water, sewer, or power, including a connection fee, a junior accessory dwelling unit shall not be considered a separate or new dwelling unit.
C. Building Code
1.
An accessory dwelling unit and a junior accessory dwelling unit shall meet minimum building code requirements prior to occupancy of the unit, except that the construction of an accessory dwelling unit shall not constitute a Group R occupancy change under the California Building Code, as described in Section 310 of the California Building Code (Title 24 of the California Code of Regulations), unless the Building Official makes a written finding based on substantial evidence in the record that the construction of the accessory dwelling unit could have a specific, adverse impact on public health and safety. Nothing in this subsection shall be interpreted to prevent the Town from changing the occupancy code of a space that was unhabitable space or was only permitted for nonresidential use and was subsequently converted for residential use pursuant to this section.
2.
Accessory dwelling units shall not be required to provide fire sprinklers if they are not required for the primary dwelling unit. The construction of an accessory dwelling unit shall not trigger a requirement for fire sprinklers to be installed in the existing primary dwelling unit.
3.
An accessory dwelling unit and a junior accessory dwelling unit shall be required to have a permanent foundation.
D. Appearance
1.
An accessory dwelling unit and a junior accessory dwelling unit shall be constructed using the same paint color(s); siding material(s); roof pitch, material(s) and color(s); door(s), window(s) and trim as the primary dwelling unit on the lot.
2.
For an accessory dwelling unit or junior accessory dwelling unit that includes a second story, any window of a second story shall be: (i) at least 60 inches above finished floor; (ii) made of obscured glass that is patterned, frosted, or textured; or (iii) located so that the center point of the window is offset by at least two feet from the center point of any second story window on an existing dwelling located on an adjacent lot.
3.
Landscaping shall comply with objective standards set forth in the State of California Model Water Efficient Landscape Ordinance, California Code of Regulations, Title 23, Division 2, Chapter 2.7 and the Town’s WELO Guidelines as set forth in Chapter 17.124 of this code.
4.
A minimum of 100 square feet shall be provided for use as common space by an accessory dwelling unit or a junior accessory dwelling unit, of which no less than half shall be directly accessible to the unit.
E.
Primary and Accessory Dwellings Not Separable. An accessory dwelling unit and a junior accessory dwelling unit shall not be sold separately from the primary dwelling unit except in accordance with Section 66341 of the California Government Code, and may be rented, provided any rental complies with Chapter 8.08 and Section 17.12.010(C)(1) of this code.
F. Occupancy and Rental
1.
Owner-occupancy is required for the single family residence in which a junior accessory dwelling unit is permitted. The owner may reside in either the remaining portion of the structure or the newly created junior accessory dwelling unit. Owner-occupancy shall not be required if the owner is another governmental agency, land trust, or housing organization.
2.
The owner of a junior accessory dwelling unit shall sign a "Notice of Restrictions: Occupancy, Sale and Rental," which the Town will record with the County Recorder's office, prior to issuance of a building permit for the junior accessory dwelling unit, acknowledging the requirements of subsections (E) and (F)(1) of this section, and including both:
a.
A prohibition on the sale of the junior accessory dwelling unit separate from the sale of the single-family residence, including a statement that the deed restriction may be enforced against future purchasers; and
b.
A restriction on the size and attributes of the junior accessory dwelling unit that conforms with this chapter and Article 3 of Chapter 13 of Division 1 of Title 7 of the California Government Code.
G.
Short-Term Rentals. Short-term rental of an accessory dwelling unit or a junior accessory dwelling unit for less than 30 days is prohibited.
H. Fees
1.
An application for an accessory dwelling unit and/or a junior accessory dwelling unit shall be submitted to the Town along with the appropriate fee as established from time to time by resolution of the Town Council.
2.
The Town may impose a fee on the applicant in connection with approval of an accessory dwelling unit for the purpose of defraying all or a portion of the cost of public facilities related to its development, as provided for in Government Code Sections 66324 and 66000(b)).
3.
The Town will not consider an accessory dwelling unit or a junior accessory dwelling unit to be a new residential use for purposes of calculating connection fees or capacity charges for utilities, including water and sewer service, unless the unit is constructed with a new single-family or multifamily dwelling.
4.
Any development impact fees charged for an accessory dwelling unit of 750 square feet or more shall be charged proportionately in relation to the square footage of the accessory dwelling unit.
5.
The Town may charge a fee to inspect an accessory dwelling unit or a junior accessory dwelling unit to determine compliance with applicable building standards.
I. Permit Approval
1.
All proposed accessory dwelling units and junior accessory dwelling units are subject to review for compliance with the terms of this chapter by the Planning Officer, via a zoning clearance. The Planning Officer shall complete the review of the application, including an application for pre-approval of an accessory dwelling unit plan pursuant to Government Code Section 65852.27, within 60 days of receipt of a complete submission.
a.
Notwithstanding the foregoing, the Planning Officer shall complete the review of an application for a detached accessory dwelling unit within 30 days of receipt of a complete submission if the application utilizes an accessory dwelling unit plan pre-approved by the Town within the current triennial California Building Standards Code rule-making cycle, or a plan that is identical to that of a detached accessory dwelling unit approved by the Town within the current triennial California Building Standards Code rule-making cycle.
2.
If the application to create or serve an accessory dwelling unit or junior accessory dwelling unit is submitted with a permit application to create or serve a new single-family or multifamily dwelling on the lot, the Planning Officer may delay approving or denying the permit application for the accessory dwelling unit or junior accessory dwelling unit until the appropriate review authority approves or denies the permit application to create or serve the new single-family or multifamily dwelling, but the application to create or serve the accessory dwelling unit or junior accessory dwelling unit shall still be considered ministerially without discretionary review or a hearing.
3.
Review of, and the denial of or granting of, an application by the Town is a ministerial action. The Planning Officer shall not approve an application or issue a permit unless the proposed accessory dwelling unit or junior accessory dwelling unit complies with the requirements of this chapter. The decision of the Planning Officer shall be final and conclusive.
4.
If the Planning Officer denies an application for an accessory dwelling unit or a junior accessory dwelling unit, the Planning Officer shall return in writing a full set of comments to the applicant with a list of items that are defective or deficient and a description of how the application can be remedied by the applicant. The Planning Officer shall not deny an application for a permit to create an accessory dwelling unit or a junior accessory dwelling unit due to the correction of nonconforming zoning conditions, building code violations, or unpermitted structures that do not present a threat to public health and safety and that are not affected by the construction of the accessory dwelling unit or the junior accessory dwelling unit.
5.
The Planning Officer shall review and issue a demolition permit for a detached garage replaced with an accessory dwelling unit at the same time he or she reviews and issues a permit for the accessory dwelling unit. The Planning Officer shall not require the applicant to post a notice or placard for the demolition of a detached garage to be replaced with an accessory dwelling unit, unless the property is within an architecturally and historically significant historic district.
6.
A permit shall not be denied for an unpermitted accessory dwelling unit that was constructed before January 1, 2020, due to either of the following:
a.
The accessory dwelling unit is in violation of building standards pursuant to Article 1 (commencing with Section 17960) of Chapter 5 of Part 1.5 of Division 13 of the Health and Safety Code.
b.
The accessory dwelling unit does not comply with Article 2 (commencing with Section 66314) or Article 3 (commencing with Section 66333) of Chapter 13 of Division 1 of Title 7 of the California Government Code or Title 17 of this code.
7.
Notwithstanding subsection (I)(5),the Planning Officer may deny a permit for an accessory dwelling unit if he or she makes a finding that correcting a violation is necessary to protect the health and safety of the public or occupants of the structure.
8.
Subsections (I)(5)and (6)shall not apply to a building that is deemed substandard pursuant to Section 17920.3 of the Health and Safety Code.
J. Permit Termination
1.
A permit for an accessory dwelling unit or a junior accessory dwelling unit shall terminate when one or more of the following occur:
a.
The construction of the accessory dwelling unit or the junior accessory dwelling unit is not commenced within one year from the date of permit issuance;
b.
The construction of the accessory dwelling unit or the junior accessory dwelling unit has been abandoned or discontinued for 18 consecutive days or more;
c.
The owner of the accessory dwelling unit or the junior accessory dwelling unit files a declaration with the Planning Officer that the permit has been abandoned or discontinued and the unit has been removed from the property; or
d. The permit has expired by its own terms
A junior accessory dwelling unit shall be built within the structure of an existing or proposed primary dwelling unit. If built within the structure of an existing primary dwelling unit, a junior accessory dwelling unit may include an addition to the primary dwelling unit of up to 150 square feet.
(Ord. 22-509 § 2; Ord. 25-532, 7/15/2025)