Chapter 18.12


18.12.010    Purpose.

18.12.020    Applicability.

18.12.030    Hillside subdivision standards.

18.12.040    Excavations and grading.

18.12.050    Development standards.

18.12.060    Building design standards.

18.12.070    Landscaping.

18.12.010 Purpose.

The Hillside (H) Overlay District is intended to protect the health, safety, and welfare of residents of the City by establishing regulations for managing the development of hillside areas. The specific purposes of the H Overlay District are to:

A.    Protect public health and safety by minimizing hazards, including soil erosion and fire danger associated with development on hillsides;

B.    Preserve and enhance San Carlos’ scenic character, including its natural hillsides;

C.    Conserve the City’s open spaces and significant natural features;

D.    Respect natural features in the design and construction of hillside development; and

E.    Design hillside development to be sensitive to existing terrain, views, and significant natural landforms and features. (Ord. 1480 (Exh. B (part)), 2015: Ord. 1438 § 4 (Exh. A (part)), 2011)

18.12.020 Applicability.

The provisions of this chapter apply to all lots and sites that have a footprint slope of nineteen and nine-tenths percent or greater and to lots and sites with a slope of nineteen and nine-tenths percent street to setback gradient. The slope is measured at the steepest point between opposite sides of the building. The Director may require a survey and slope analysis to determine whether the provisions of this chapter apply to a specific property or development. These regulations may be combined with any district. In the event of a conflict between the provisions of this chapter and any underlying base district, the most restrictive provisions shall apply. (Ord. 1480 (Exh. B (part)), 2015: Ord. 1438 § 4 (Exh. A (part)), 2011)

New graphic coming soon.

18.12.030 Hillside subdivision standards.

A.    Further Reduction in Number of Allowed Lots. The review authority may reduce further than required by this section the maximum number of lots in a new subdivision based upon site-specific problems or constraints identified through the environmental review of the proposed subdivision.

B.    Building Site Requirements. Each proposed lot shall be designed and located to provide at least one building site where all proposed structures can comply with all other applicable requirements of this title.

C.    Roads. Each new road shall follow natural terrain contours to the maximum extent feasible to minimize grading. Proposed driveways shall comply with the requirements of Section 18.12.050, Development standards. (Ord. 1443 § 4 (Exh. A (part)), 2012; Ord. 1438 § 4 (Exh. A (part)), 2011)

18.12.040 Excavations and grading.

The following requirements shall be in addition to all other requirements which may from time to time be adopted by the City in various building and engineering regulations, unless such regulations specifically repeal or state they supersede the standards of this section.

A.    Grading and excavations shall result in the minimal disturbance feasible to the terrain and natural land features.

B.    Existing trees and native vegetation shall be retained to the extent possible to stabilize hillsides, reduce erosion and to preserve the natural scenic beauty of the area.

C.    Grading plans shall to the extent feasible balance cut and fills on site so that the import and export of materials for development is minimized.

D.    All areas of the site not under structures with a final slope greater than fifteen percent shall be left uncovered by impervious surface and may be disturbed only as may be necessary to develop the site.

E.    Final contours and slopes shall generally reflect existing landforms and be compatible with existing grades on adjoining property.

F.    Slopes created by grading of the site shall not exceed thirty percent.

G.    The outside corners or edges of all cut and fill slopes except at the tops of slopes shall be rounded to eliminate the sharp corners and shall have a minimum curvature radius of at least five feet.

H.    Exceptions to the standards of this subsection may be approved by the Planning Commission if the following findings are made:

1.    The project design alternative substantially meets the purposes of the H Overlay District; and

2.    The project incorporates alternative design solutions that minimize grading, retain more of the project site in its natural state, minimize visual impacts, protect significant trees, or protect natural resources and result in a demonstrably superior project designed with greater sensitivity to the natural setting and compatibility with nearby structures. (Ord. 1438 § 4 (Exh. A (part)), 2011)

18.12.050 Development standards.

A.    General Site Planning Standards. Each structure shall be located in the most accessible, least visually prominent, most geologically stable portion or portions of the site, and at the lowest feasible elevation. Structures shall also be aligned with the natural contours of the site. Siting structures in the least prominent locations is especially important on open hillsides where the high visibility of construction should be minimized by placing structures so that they will be screened by existing vegetation, depressions in topography, or other natural features.

B.    Parking Front Setback Adjustment. In order to reduce grading, required parking (including a private garage) may be located, at the discretion of the Director, as close as five feet to the street property line; provided, that portions of the dwelling and accessory structures other than the garage shall comply with the setback requirements of the base zoning district.

C.    Natural State. A minimum area of twenty-five percent of the lot area plus the percentage figure of average slope, not to exceed a maximum of eighty-five percent, must remain in its natural state. This standard may be waived or reduced for lots zoned PD or developed with clustered development subject to approval by the review authority.

D.    Site Access, Driveways. Each driveway shall follow natural terrain contours to the maximum extent feasible to minimize grading, and also shall comply with the following standards:

1.    Maximum Grade. The finished grade of a driveway shall conform to the finished grade of the lot, but in no case shall exceed an average grade of eighteen percent.

2.    Agency Review. The location and design of any driveway shall be referred to the Fire Department for review and comment as to on- and off-street safety of vehicles, vehicle passengers and pedestrians, and access for emergency vehicles.

E.    Retaining Walls. Large retaining walls in a uniform plane shall be avoided. Retaining walls shall be divided into terraces with variations in plane and include landscaping to break up the length of walls and to screen them from view. No retaining wall located in the front or rear yard area shall be higher than six feet, and must incorporate a three-foot recessed offset feature every thirty feet, or other methods of articulation. (Ord. 1480 (Exh. B (part)), 2015; Ord. 1438 § 4 (Exh. A (part)), 2011)

18.12.060 Building design standards.

A.    Height Limits. A proposed structure shall comply with the setback requirements of the base zoning district and the following:

1.    Overall Height Limit. The maximum overall height of a structure shall not exceed a height of thirty-five feet, measured from the lowest elevation on the site where the structure touches finished grade, to the highest point of the roof.

2.    Downhill Facing Building Elevation. The building elevation facing the downslope shall have a maximum height of twenty feet from finished grade with sufficient articulation from that building face to the next highest story to minimize the visual height and bulk as viewed from the lowest finished grade.


B.    Articulation. The apparent size of exterior wall surfaces visible from off the site shall be minimized through the use of single-story elements, bays, recesses, stepbacks, overhangs, landscaping, and/or other means of horizontal and vertical articulation to create changing shadow lines and break up massive forms.

C.    Foundation Design. The use of multi-level foundations (floor levels separated by a minimum of four feet) shall be the standard design for residential structures unless an alternative design, with less grading, is approved through the design review process as more appropriate for the site.

D.    Underfloors. Areas between the lowest floor and finished grade shall not exceed six feet in height and shall be completely enclosed with fire-retardant materials to prevent exposure to wildfire hazard.


E.    Decks. No portion of the walking surface of a deck with visible underpinnings shall exceed a height of six feet above grade. Decks shall be integrated into the architecture of the house, and not appear as an add-on to the primary building mass.

F.    Colors and Materials. A mixture of materials and color shall be used to blend structures with the natural appearance of the hillside:

1.    Based upon the graphic principle that darker colors are less noticeable than light colors, darker tones, including earth tones, shall be used for building walls and roofs on highly visible sites so that structures appear to blend in with the natural terrain.

2.    Exterior finish materials shall be appropriate for the architectural style of the structure and compatible with the hillside environment.

3.    In areas of potential high fire hazard, exterior building materials shall be fire-retardant. (Ord. 1480 (Exh. B (part)), 2015; Ord. 1438 § 4 (Exh. A (part)), 2011)

18.12.070 Landscaping.

A.    Required Landscaping. Landscaping shall provide for the following:

1.    Screening of retaining walls over four feet in height, accessory structures, and buildings visible from a downslope;

2.    Screening of parking areas in multiple residential or nonresidential developments; and

3.    Slope stabilization for all cut, fill, and natural slopes of three feet or more in vertical height with deep-rooted plants.

B.    Fire Hazards. Fire-resistant, drought-tolerant species shall be used where appropriate to reduce fire hazards.

C.    Installation and Maintenance. Landscaping shall be installed and maintained consistent with the regulations of Chapter 18.18, Landscaping. (Ord. 1438 § 4 (Exh. A (part)), 2011)