Union City City Zoning Code
CHAPTER 18
31 SB 9 SUBDIVISIONS AND DEVELOPMENT PROJECTS
§ 18.31.010 Purpose.
The purpose of this chapter is to provide objective zoning standards for SB 9 Housing Developments within single-family residential zoning districts, to implement the provisions of State law as reflected in Government Code Section 65852.21 et seq. and Section 66411.7 et seq., and to facilitate the development of new residential units in a manner compatible with existing single-family residential uses and ensure standards of public health and safety.
The following zones are identified as single-family residential zoning districts; R-5000, RS-6000, RS-6000-H, RS-6000D, RS (S), RS (s) 3000, RS 4500, and 511.
(Ord. 900-22 § 4, 2022)
§ 18.31.020 Definitions.
For purposes of this chapter, the following definitions apply:
means a primary dwelling, an accessory dwelling unit or a junior accessory dwelling unit as defined in Chapter 18.08.
means the single-family residence on the property prior to the approval of an SB 9 unit or urban lot split.
means a project containing one or more SB 9 units and may include an urban lot split.
means the subdivision of an existing parcel into two parcels pursuant to California Government Code Section 66411.7 and meeting all the criteria and standards set forth in this chapter.
(Ord. 900-22 § 4, 2022; Ord. 2025-002, 3/25/2025)
§ 18.31.030 Number of units allowed.
A.
When not located on a site subject to an approved or proposed urban lot split: (i) a maximum two SB 9 units are permitted per parcel; and (ii) either one accessory dwelling unit and/or junior accessory dwelling unit per SB 9 unit or primary unit meeting the requirements in Chapter 18.34 is permitted, for a total of up to four dwelling units on the subject property.
B.
When located on a site subject to an approved or proposed urban lot split, a maximum two SB 9 units are permitted per parcel resulting from the urban lot split, for a total of two units on each of the two resulting parcels. Should a resulting parcel include only one primary or SB 9 unit, either one SB 9 unit, accessory dwelling unit, or junior accessory dwelling unit is permitted.
(Ord. 900-22 § 4, 2022)
§ 18.31.040 Eligibility.
A.
Applications for SB 9 Housing Developments are eligible for ministerial approval on parcels located within a single-family residential zoning district.
B.
To be eligible for an SB 9 Housing Development, the proposed housing development shall meet all of the following criteria:
1.
Not be located on a site as identified in Government Code Section 65913.4(a)(6)(B) to (K), or as amended:
2.
Does not require the demolition or alteration of:
a.
Housing subject to a recorded covenant, ordinance or law that restricts rents to levels affordable to persons and families of moderate, low or very low income.
b.
Housing occupied by tenant(s) in last three years as determined by the City based on City records or information requested by the City from the applicant.
3.
Owner has not exercised the owner's rights under Government Code Chapter 12.75 (commencing with Section 7060) of Division 7 of Title 1 to withdraw accommodations from rent or lease within last 15 years.
4.
Does not demolish more than 25% of existing exterior structural walls if the site has been occupied by a tenant in the last three years.
5.
Is not located within a historic district or property included 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 City or County landmark or historic property or district pursuant to a City or County ordinance. For purposes of this chapter, this includes the properties located within the Landmark and Historic Preservation Overlay Zone, or included in the California Register of Historical Resources, the National Register of Historic Places, or considered a historic resource after completion of a historic resource evaluation.
C.
For urban lot splits, the following criteria must also be met:
1.
Parcel has not been established through exercise of an urban lot split, as provided for in this chapter.
2.
Neither the owner of the parcel being subdivided nor any person acting in concert with the owner has previously subdivided an adjacent parcel using an urban lot split as provided for in this chapter. For the purposes of this criterion, "adjacent parcel" means a parcel sharing any portion of its lot line(s) with the parcel being subdivided using the provisions of the urban lot split.
(Ord. 900-22 § 4, 2022)
§ 18.31.050 Procedure and application-Required information for all SB 9 housing developments.
A.
An application for an SB 9 Housing Development shall be made to the Zoning Administrator on a form prescribed by the Director which shall include the following data:
B.
Plans shall include the contents as required by the SB 9 Housing Development Checklist as prescribed by the Director.
C.
The application shall be accompanied by the items identified by the SB 9 Housing Development Checklist as prescribed by the Director.
D.
An application fee as established by the City Council by resolution.
(Ord. 900-22 § 4, 2022)
§ 18.31.060 Procedure and application-Required information for urban lot split.
In addition to the information listed in Section 18.31.050, the following shall be provided for projects involving an urban lot split:
A.
The plans for urban lot split shall be prepared by a person qualified to prepare subdivision maps, such as a registered civil engineer, or licensed surveyor. Such urban lot split shall be in full compliance with the requirements of this chapter. Topography and boundaries of said urban lot split shall be certified as to accuracy by a registered civil engineer or licensed land surveyor, and all public improvements shall be designed by a registered civil engineer.
B.
Applicant shall sign an affidavit on a form provided by the City stating the owner intends to occupy one of the housing units on a resulting parcel as his or her principal residence for a minimum of three years from the date of the approval of the urban lot split, except this shall not apply to a community land trust or a qualified nonprofit corporation.
C.
Plans shall include the contents as required by Section 17.20.030 and as required by the appropriate urban lot split checklist as prescribed by the Director or City Engineer.
D.
An application fee as established by the City Council by resolution.
(Ord. 900-22 § 4, 2022)
§ 18.31.070 Density.
An SB 9 Housing Development does not increase the density of the lot upon which it is located.
(Ord. 900-22 § 4, 2022)
§ 18.31.080 Action of Zoning Administrator.
A.
An application to create an SB 9 Housing Development, with or without an urban lot split, shall be ministerially reviewed, and either approved or denied, by the Zoning Administrator based on the requirements of this chapter and application law.
B.
Notwithstanding subsection A, above, an application for an SB 9 Housing Development may be denied if the Chief Building Official or their designee, upon making written findings to the Zoning Administrator or their designee, finds the project would have a specific, adverse impact upon public health and safety or the physical environment and for which there is no feasible method to satisfactorily mitigate or avoid the specific, adverse impact.
(Ord. 900-22 § 4, 2022)
§ 18.31.090 Development standards.
A.
The standards set forth in this chapter shall not preclude the construction of up two dwelling units per parcel and shall not preclude each dwelling unit from being at least 800 square feet in floor area. To the extent that any development standard precludes such development, the development standard shall be reduced or eliminated only to the extent necessary to allow the development of up to two dwelling units, of at least 800 square feet, per parcel.
B.
All SB 9 units shall have separate utility connections and meters. If an accessory dwelling unit becomes a primary dwelling unit, a separate utility connection for the reclassified unit shall then be required.
C.
All SB 9 units, whether attached or detached, shall be designed for separate conveyance, in accordance with applicable Fire Code and Building Code requirements.
D.
Setbacks. SB 9 units shall meet the setbacks established by the zoning district for primary structures except as provided below:
1.
Existing Structures. No setback shall be required for an existing structure, or a structure constructed in the same location and to the same dimensions as an existing structure.
2.
Interior Side and Rear Setbacks. SB 9 units shall be setback from interior side and rear lot lines a minimum of four feet.
3.
Exterior Side Setbacks. On the street side of a corner lot, the street side yard shall not be less than 10 feet.
E.
Height. SB 9 units shall be subject to the height limitations established by the zoning district for primary structures except:
1.
The maximum height of the portion of a SB 9 unit located between the four foot setback line established by this chapter and the limit of the rear, side, or street side yard area established by zoning district is 16 feet, as measured from the lowest grade adjacent to the structure to the highest ridge or top of the structure.
F.
Lot Coverage. SB 9 units on the same parcel shall be cumulatively limited to the lot coverage allowed by the residential zoning district that the parcel is located, except that in no case shall a single unit be larger than 2,000 square feet.
G.
Building Separation. SB 9 units shall be separated from accessory structures on the same parcel, parcels resulting from an urban lot split, or adjacent parcels by a minimum of five feet, except that the distance between a main structure and an accessory structure shall be allowed to be closer than six feet if all the following conditions are met:
1.
These separation requirements would cause SB 9 unit to conflict with the minimum setbacks or unit size otherwise allowed by this chapter.
2.
All of the requirements of the Building and Fire Codes are met.
3.
If accessory structures are not located closer than four feet to any side or rear lot line.
H.
Parking. One off-street, covered and enclosed parking space shall be provided per SB 9 unit, except if the parcel is located:
I.
Addressing. Street addresses shall be assigned to all units to assist in emergency response prior to building permit issuance. An address shall be placed at the front of the lot, visible from the public right-of-way, and at the main entrance to the unit (if not visible from the public right-of-way).
J.
Except where indicated in this chapter, SB 9 Housing Developments shall comply with other Zoning and Building Code requirements generally applicable to residential construction in the applicable zone where the property is located.
K.
Development standards set forth in a planned unit development or specific plan shall apply to any SB 9 Housing Development except that any such planned unit development or specific plan standard cannot be applied if it would either: (1) result in a conflict with standards set forth by State law for an SB 9 housing development; or (2) preclude an SB 9 Housing Development that meets the applicable requirements of State law or this chapter.
L.
SB 9 Housing Development shall comply with the following owner occupancy requirements:
1.
In the case where there is no urban lot split, rental of any accessory dwelling unit or junior accessory dwelling unit associated with a primary or SB 9 unit shall be as specified in Chapter 18.34.
2.
In the case where there is an urban lot split, the applicant shall sign an affidavit on a form provided by the City stating that the applicant intends to occupy one of the dwelling units as his or her principal residence for a minimum of three years from the date of approval of the urban lot split.
M.
Rental of any SB 9 unit shall be for more than 30 consecutive days.
(Ord. 900-22 § 4, 2022)
§ 18.31.100 Subdivision Standards-Urban lot split.
Notwithstanding Title 17 of this Code, the City shall ministerially approve a parcel map for an urban lot split, subject to meeting all of the requirements in this chapter.
A.
The urban lot split shall result in no more than two parcels and one of the two parcels resulting from the urban lot split shall not be smaller than 40% of the lot area of the original parcel.
B.
The newly created parcels shall conform to all of the following standards:
1.
Each lot shall be a minimum size of 1,200 square feet.
2.
The side lot lines of all lots, to the extent possible, shall be at right angles to the street which the lot faces, or approximately radial to the center of curvature, if such street is curved. Side lines of lots shall be approximately radial to the center of curvature of a cul-de-sac on which the lot faces.
3.
Each parcel shall provide for direct vehicular access to and have a minimum frontage of 30 feet on the public right-of-way, except for flag lots, where the frontage shall be the width needed to meet access standards as specified in this chapter.
4.
Lot depth shall not exceed two times the lot width except as provided below.
a.
The Director may approve a lot depth between two and three times the width where, based on the physical characteristics of the land, a greater lot depth would result in a better lot configuration considering the established development pattern in the area and efficient utilization of land.
C.
Flag lots, if proposed, shall meet the following standards:
1.
A flag lot shall be allowed with an urban lot split in a situation where a conventionally configured lot would not allow for a second lot of at least 1,200 square feet, accommodating two housing development units of at least 800 square feet each.
2.
Front, side, and rear yards for the purposes of identifying required setbacks shall follow the orientation established by the adjacent lots unless otherwise determined by the Zoning Administrator and/or their designee.
3.
The minimum width of the access corridor portion of the flag lot shall be 12 feet paved, except where greater width is required for Fire Department access.
4.
A fence may be constructed between the access corridor of a flag lot and the adjacent parcel consistent with the requirements listed in Section 18.32.040, except that the fence height may not exceed three feet within the front yard area of the adjacent property.
5.
All fire code requirements shall be met, including, but not limited to: access, driveway length and width, turnarounds, clearance, road grades, fire hydrant connections.
D.
Driveways shall conform to the minimum standards set by the Public Works Department standard detail STD-201, or as specified in the Fire Code if emergency vehicle access is required.
E.
Two driveways on less than 70 feet of total frontage are permitted only when necessary to provide access to both parcels resulting from the urban lot split. In this case, either the aggregate width of two separate driveways or a combined shared driveway must comply with the dimensions set forth by the Public Works Department standard detail and the driveway shall be configured to avoid unnecessary loss of available curbside parking in the neighborhood. Shared driveways and shared curb cuts are encouraged whenever possible.
F.
Public service easements shall be provided within the subdivision where required for public utility purposes, in accordance with Title 17 of this Code.
(Ord. 900-22 § 4, 2022)
§ 18.31.110 Design standards.
All SB 9 Housing Developments shall meet the following standards:
A.
The standards set forth in this chapter shall not preclude the construction of up to two SB 9 units per parcel and shall not preclude each SB 9 unit from being at least 800 square feet in floor area.
B.
Building Façades and Materials.
1.
No façade facing a public right-of-way shall run in a continuous plane of more than 10 feet and no façade facing an interior lot line shall run in a continuous plane of more than 15 feet without incorporating one or more of the following:
a.
A vertical wall shift at least one foot in depth;
b.
A change in material type;
c.
Windows or building entrances;
d.
A projection such as a stoop, bay window, or overhang; or
e.
Exceptions. Exceptions may be granted by the Director where the Director finds that adequate design features have been incorporated to create visual variety and avoid a bulky or monolithic appearance.
2.
A minimum of three exterior colors or a combination of materials and colors shall be used on the building façade.
a.
Stucco must be used in combination with a secondary material.
3.
Transitions for both materials and colors shall be located at internal corners.
a.
Exceptions. Exceptions may be granted by the Director where the Director finds that transitions in other locations create visual variety or to accommodate a complete architectural style.
4.
Second-story façades shall incorporate the following:
a.
A minimum of a six foot inset from the front wall plane;
b.
A minimum of an 18 inch inset from the side and rear wall plane;
c.
Exceptions. Exceptions may be granted by the Director to accommodate a complete architectural style or alternative detailing that complement the architectural character of the existing development or neighborhood.
5.
Where chimney extensions are involved, the extension shall incorporate the same materials as the existing chimney.
C.
Windows and Glazing.
1.
All windows shall incorporate the following:
a.
Trim at least three inches in width must be provided around all windows, or
b.
Windows must be recessed at least two inches from the plane of the surrounding exterior wall.
c.
Exceptions may be granted by the Director to accommodate alternative window design complementary to the architectural style of the structure.
2.
Upper story windows located less than 10 feet from side and/or rear lot lines and facing side and/or rear yard of an adjacent property shall be located to maximize privacy for adjacent properties by using at least one of the following techniques:
a.
The sill height located a minimum of 60 inches above the finished floor.
b.
The location of the window is such that the centerline of the glazing is offset greater than 15 lateral feet from the centerline of any glazing on an existing adjacent primary structure.
c.
Any window located partially or entirely below 60 inches from the finished floor consists of frosted or obscured glazing.
d.
As used in this section, frosted or obscure glass is glass which is patterned or textured such that objects, shapes, and patterns beyond the glass are not easily distinguishable.
D.
Roof Form and Detailing.
1.
New structures shall provide a roof pitch no less than two and one-half (2.5) inches of vertical rise for each 12 inches of horizontal run.
a.
Mansard roofs shall be prohibited.
2.
SB 9 units resulting from alterations or additions to an existing structure shall provide the same roof form, material, and color as the existing structure.
3.
New buildings shall provide a roofing material that is the same as the predominant roofing material throughout properties within 100 feet.
4.
Roof material and color shall be the same throughout the entirety of the roof.
5.
Overhanging eaves shall extend a minimum of 12 inches beyond the supporting wall.
6.
The roof form and materials of garages shall be the same as the materials and detailing of primary and SB 9 units.
7.
Exceptions. Exceptions may be granted by the Director to accommodate a complete architectural style or alternative roof forms and detailing that complement the architectural character of existing development.
E.
Principal Entrances.
1.
Each street frontage shall have at least one principal entry oriented toward it.
2.
The principal entrance may be an individual entrance to a single unit or a shared entrance that provides access to more than one unit.
3.
The principal entry shall be emphasized utilizing at least one of the following methods:
4.
Street-facing front entries shall be clearly identifiable and connected to the public street by a pedestrian path with a minimum width of three feet.
5.
Exceptions. The Director may approve alternative principal entrance designs that create a welcoming entry feature such as a trellis, landscaped courtyard entry, enhanced walkway, columns or other architectural features.
F.
Balconies. Usable balconies and upper-story decks are prohibited on SB 9 units. Decorative/faux balconies that are less than two feet in depth and are not accessible from the unit are allowed.
G.
Exterior Stairways. Exterior stairways providing access to an upper story are prohibited.
H.
Walls, Fences and Hedges. Walls, fences, and hedges shall meet the requirements identified in Section 18.32.040.
I.
Mechanical and utility equipment shall be concealed as viewed from the public right-of-way. Ground-mounted equipment shall be screened by a combination of walls or fencing and landscaped plant material up to a maximum height of three feet. In no case shall screening cause a sight obstruction to pedestrian, bicycle, or vehicular traffic as determined by the City Engineer. Roof mounted equipment shall be screened by the use of architectural screens or roof wells.
J.
Storage of waste containers shall not be located within private driveways or be visible from the public right-of-way.
K.
SB 9 Housing Developments shall comply with the following landscaping requirements:
1.
Lots with aggregate new landscaped area equal or greater to 500 square feet or replaced landscaped area equal or greater to 2,500 square feet shall comply with the Chapter 18.112 water efficient landscaping and the City's Residential Landscape Standards Policy Statement.
3.
Landscaping used to screen views of storage areas, trash enclosures, mechanical or HVAC equipment, irrigation and plumbing equipment, and transformers shall be a maximum of three feet in height. In no case shall screening cause a sight obstruction to pedestrian, bicycle, or vehicular traffic as determined by the City Engineer.
L.
Garages constructed for SB 9 units shall meet the following standards:
1.
Garages shall comply with the standards identified in Section 18.32.160(C).
2.
Detached garage shall comply with the standards identified in Section 18.32.020(I).
3.
Front entry attached garages shall be articulated and offset from the adjacent wall plane.
4.
Garage doors located in a stucco wall shall be recessed a minimum of three inches from the surrounding building wall.
5.
Garage doors located in wood clad (or similar) siding, or masonry walls shall provide surrounding trim with a minimum width of three inches.
(Ord. 900-22 § 4, 2022)