The following property development standards shall apply to all accessory dwelling units other than those state exempt ADUs permitted pursuant to Sections 10-2.3.503(A)(1)(a) through (A)(1)(c), (A)(2)(a), and (B), located in the base districts where they are a permitted use. Pursuant to Section
66323 of the California Government Code, accessory dwelling units permitted pursuant to Sections 10-2.3.503(A)(1)(a) through (A)(1)(c), (A)(2)(a), and (B) are exempt from all property development regulations (including, but not limited to, setbacks, height, density, lot coverage, distance between buildings, minimum or maximum floor area ratio, design review, landscaping, storage space for residential units, nonconforming conditions, elevators, parking and loading, hillside performance standards, and property development standards for accessory dwelling units) contained elsewhere in this chapter, including any planned development district or overlay zone, and also the provisions of Title 3, Chapter 8,
Preservation of Trees on Private Property.
A. Property Development Regulations. All property development regulations of the base district in which the property is located shall apply, except as otherwise specified in this article. In the P-D and H-P-D or their successor districts, where no standards are specified, the development standards based on the district that most closely matches existing development in regards to land use and lot size (but not over the lot size) shall apply. The following exceptions shall apply in all base districts:
1. No greater than a four (4) foot setback from any interior side, corner side, or rear lot line shall be required for an accessory dwelling unit.
2. The maximum lot coverage, minimum open space, front setback, and floor area ratio shall be waived in the amounts necessary to accommodate an accessory dwelling unit with a gross floor area of up to eight hundred (800) square feet in compliance with the requirements of subsection (A)(1) of this section.
3. The maximum building height of the base district shall apply to accessory dwelling units, or portions thereof, that comply with the minimum setbacks of the base district. For all other accessory dwelling units, or portions thereof, the maximum building height shall be as follows:
a. Sixteen (16) feet for a detached accessory dwelling unit, except as follows:
i. Eighteen (18) feet shall be allowed on lots within one-half (1/2) mile walking distance of a major transit stop or a high-quality transit corridor, as those terms are defined in Section
21155 of the California Public Resources Code, plus an additional two (2) feet to accommodate a roof pitch matching that of the primary dwelling structure.
ii. Eighteen (18) feet shall be allowed on lots with an existing or proposed multilevel multifamily dwelling.
b. Twenty-five (25) feet, but not more than two (2) stories, for an attached accessory dwelling unit.
4. Notwithstanding any other provisions, when a new accessory dwelling unit structure is constructed in the same location and to the same dimensions as an existing structure (as measured by existing width, length, and height), the setbacks and height of the existing structure shall apply. This provision shall not prohibit a new structure that is intended to replace an existing structure from deviating from the dimensions of the existing structure, provided such deviation complies with all regulations applicable to a new structure.
B. Size. The maximum gross floor area for an accessory dwelling unit shall be based on net lot area as follows:
Net Lot Area: | Maximum Gross Floor Area: |
|---|
Studio or One Bedroom | Two or More Bedrooms |
|---|
14,999 square feet or less | 850 square feet | 1,000 square feet |
15,000 to 19,999 square feet | 900 square feet | 1,000 square feet |
20,000 square feet or more | 950 square feet | 1,000 square feet |
In addition to the foregoing limits, if greater than eight hundred (800) square feet, the gross floor area of an attached accessory dwelling unit connected to an existing single-family dwelling shall not exceed fifty (50) percent of the gross floor area of the existing single-family dwelling or religious assembly use.
C. Design.
1. Lots With a Single-Family or Multifamily Dwelling.
a. Exterior Entrances. An exterior entrance shall be provided for all accessory dwelling units, independent of the exterior entrance for the main dwelling. No exterior entrance to an attached accessory dwelling unit shall be located on the same building side as the main entrance to the main dwelling.
b. Internal Connections. All internal connections between an attached accessory dwelling unit and the main dwelling shall be secured by a door which can be locked independently from either side.
c. Architecture. The accessory dwelling unit shall be architecturally consistent with the main building by meeting the following requirements:
i. Exterior Siding and Trim. The accessory dwelling unit shall use the same exterior siding and trim materials as the main building, such as wood paneling or shingles, stucco, etc. When a main building uses multiple materials for siding and/or trim, the accessory dwelling unit shall use whichever material occupies the greatest percentage of the main building's siding and/or trim, as applicable.
ii. Building Shape. Non-rectangular (circular or triangular) floor plans, or exterior elements of floor plans, are not permitted unless matching the shape of the main building floor plan.
iii. Roof Form/Pitch. The accessory dwelling unit shall use the same roof form (e.g., hip, gable, etc.) and pitch as the roof form and pitch covering the greatest portion of the main building.
iv. Roof Materials. The accessory dwelling unit shall use the same roof material as the main building. When a main building uses multiple roof materials, the accessory dwelling unit shall use whichever material occupies the greatest percentage of the main building's roof.
v. Windows. The accessory dwelling unit's windows shall match at least two (2) of the following window design features of the main building's front facade (or street side facade if containing the main building entrance):
III. Trim material and/or color.
vi. Exceptions. The requirements of subsections (C)(1)(c)(i), (C)(1)(c)(iv), and (C)(1)(c)(v) of this section may be waived as follows:
I. If any standard conflicts with the California State Building Code or the City's Municipal Code, such standard shall be waived.
II. If any of the listed materials or window style, etc., for an existing dwelling are no longer commercially available, such standard may be waived; provided, that the accessory dwelling unit shall use a material or window style as close to the original as feasible, as determined by the Community Development Director.
III. Fiber cement or other composite materials, such as Hardie siding, may be used in lieu of natural wood siding, trim and/or roof materials; provided, that the dimensions of the new materials match those of the existing ones, as determined by the Community Development Director.
2. Lots With a Religious Assembly Use.
a. Attached accessory dwelling units shall be subject to the above provisions for lots with single-family or multiple-family dwellings, except that the accessory dwelling unit shall match the predominant building form, roof, and window placement/type of the main building, not including minarets, spires, and other architectural features that extend from the main roof, or stained-glass windows. Where stained glass-windows are the predominant window type of the main building, the accessory dwelling unit shall match the window shape but not the stained-glass treatment.
b. Detached accessory dwelling units shall be subject to the Design Review Standards and Guidelines for single-family dwellings, except that they shall utilize the same colors for exterior siding and trim as the predominant colors based on square footage covered of the main building. Exceptions may be requested as provided in the Standards and Guidelines.
D. Additional Design Standards for Garage Conversions. In cases where an accessory dwelling unit is created through the conversion of an existing garage and an addition over one hundred fifty (150) square feet is proposed, the garage conversion shall be architecturally consistent with the main building through one (1) of the following options:
1. The garage door is left operational to provide access to a storage space that is separated from the accessory dwelling unit by an interior partition wall. The partition wall shall not be constructed in such a manner as to fully or partially prevent the operation of the garage door. Adding new window openings or pass doors onto the garage door is prohibited.
2. The garage door is removed entirely and replaced with fenestration elements that are architecturally consistent with the main building as outlined under subsection
(C) of this section. A landscaped area shall be installed to provide a minimum of three (3) feet of separation between the driveway and the former garage door. This landscaped area may be reduced to a depth as little as one (1) foot to maintain a minimum driveway length of eighteen (18) feet, as measured from the street line. No landscaping is required when the driveway serving the existing garage is less than nineteen (19) feet in length, as measured from the street line.
E. Off-Street Parking. No parking spaces are required for accessory dwelling units.
F. Second-Story Windows. Second-story windows located within ten (10) feet of a side or rear property line in an R, D-3, or SFH-PD1 district, or on a lot containing a single-family dwelling or religious assembly use in an M-3, H-P-D, or P-D district, shall have a sill height of not less than five (5) feet above the second-story floor.
G. Additional Limitations for Hillside Lots. The following limitations shall apply to any accessory dwelling unit located on any lot, or portion thereof, with an average slope of fifteen (15) percent or greater (as defined by one (1) of the density determination methods described in Section
10-2.3.406), unless located within the Core Area or Rossmoor (as defined in Section
10-2.3.402,
Definitions):
1. Due to the high levels of risk of property damage and personal injury, there shall be no grading or construction of any kind on any portion of the site where the true slope exceeds thirty percent (30%).
2. There shall be no grading or construction of any kind within the area surrounding any highly protected tree for a distance of one and one-half (1-1/2) times the distance from the trunk to the dripline (as those terms are defined in Section
3-8.02).
3. Grading shall only be allowed for driveways; garage pads; cuts under the accessory dwelling unit; cuts on the uphill side of the accessory dwelling unit which are screened from public view by the accessory dwelling unit or existing vegetation; sight distance requirements; drainage; and soil stability purposes. All grading shall be done in such a manner that it presents a finished look of rounded slopes. All exposed graded areas shall be hydroseeded/relandscaped to minimize erosion.
4. No accessory dwelling unit shall be constructed within a one hundred (100) foot vertical drop from the ridgeline of any visually prominent ridge (as defined in Section
10-2.3.402) or in such a manner that it breaks the skyline of any visually prominent ridge as viewed continuously for more than one thousand (1,000) feet from any freeway, arterial, or scenic corridor within the City limits.
5. No accessory dwelling unit shall be constructed upon a rock outcropping which covers more than two hundred (200) square feet of land area.
6. No accessory dwelling unit shall be built within fifty (50) feet of a fault line, within fifty (50) feet of the top of a creek bank (as defined in Section
10-2.3.402), or within that setback from a known landslide area recommended in a soils report prepared for the proposed development. Where significant riparian vegetation exists beyond the limits required above for creek setbacks, the setback line shall be extended to include such areas.
7. All mechanical equipment on site shall be enclosed on all sides with an opaque vertical screen or wall at least as tall as the tallest piece of equipment.
8. Exterior lighting shall be designed and installed in such a manner that the light source is shielded from view off the site.
9. The ground floor of the portion of a building containing an accessory dwelling unit shall not be located more than four (4) feet above the base elevation (as defined in Section
10-2.1.303).
(§ 7, Ord. 2018, eff. 8/14/2003; § 1, Ord. 2027, eff. 5/6/2004; § 6, Ord. 2173, eff. 10/20/2017; §§ 13, 14, Ord. 2188, eff. 3/8/2019; § 23, Ord. 2210, eff. 10/22/2021; § 4, Ord. 2239, eff. 7/5/2024; § 3, Ord. 2241, eff. 7/19/2024; § 3(3), Ord. 2246, eff. 11/15/2024; § 3, Ord. 2250, eff. 9/5/2025; Formerly 10-2.3.503)