Introduction

This handout summarizes San Rafael’s zoning regulations and construction requirements on single-family hillside lots. Design review is required for new development or additions made to structures on residential hillside properties, pursuant to San Rafael Municipal Code Chapter 14.12 and Chapter 14.25. Prior to submittal of plans, it is recommended that the applicant visit the planning division and discuss their proposed project with a planner. 

What Constitutes a Hillside Lot? 

A hillside lot generally means any residential parcel with an average slope over twenty-five percent (25%), and lots in the Hillside Resource Residential, Hillside Residential general plan land use designations; which would have an Hillside (-H) Overlay Zone District applied to the base district designation. Hillside lots may also occur in the Low Density Residential, Medium or High Density Residential land use designations.

Property Development Standards (-H) 

Development standards shall be those of the underlying residential zoning district with which a hillside development overlay district is combined. The –H district requirement shall govern where conflicts arise between the base zoning district and the –H overlay standard. For instance, the Upper Story floor level restriction is not utilized in review of hillside design which instead governs bulk and mass through building FAR, stepback, natural state and height limit standards. However, Medium or High Density Residential is only subject to the –H Overlay Height and Building Stepback requirements. The standards are inapplicable to nonresidential properties.

Exceptions to –H development standards may be approved by the city council, subject to additional findings required by Chapter 14.12 and upon the recommendation of the Design Review Board and the Planning Commission, when the applicant has demonstrated that alternative design concepts carry out the objectives of Chapter 14.12

Building Stepback: The building stepback is established to limit height to avoid excessive building bulk. Walls facing downhill, and front and side property lines within fifteen feet (15’) of the building envelope are subject to twenty-foot (20') height limit (unarticulated wall plane) measured from existing grade. To allow for design flexibility, an “encroachment” is permitted to allow taller vertical wall elements along twenty-five percent (25%) of the overall building length.  

Floor Area Ratio (FAR) and maximum square footage: 10% of lot area plus 2,500 square feet.  6,500 square feet absolute maximum 

Height of Structures: 30 feet for dwelling and 15 feet for accessory structures, measured from grade plane.

On a lot with a slope over 25%, height is measured vertically from the existing grade to the uppermost point of the roof edge or other feature perpendicular to that grade. 

Natural State: An area equal to 25% of the site plus the Average Slope % of the lot that must remain undeveloped and undisturbed. Incidental minor trails and landscaping that enhances the natural environment are permitted. 

Setback Waivers: Structures may encroach into a required yard or setback not more than one-half (1/2) of the required yard or setback with the recommendation of the design review board that the decrease minimizes the impact of hillside development and grading and a compensating increase in setback is required in the opposing setback. 

Average Slope Calculation: The measurement of slope of a lot before grading is determined by this formula:  

(.00229)(I)(L) / (A)

.00229 is the conversion factor for square feet  

“I” is the contour interval in feet  

“L” is the sum of the length of the contour lines in feet  

“A” is the size of the lot in acres 

 Tree Replacement: Three trees shall be planted for every significant tree removed.  Significant tree: oaks that measure six-inches in diameter and other trees that measure 12-inches in diameter at four and one-half feet above the root crown. 

Ridgeline Development: Development on hillside slope lots located within one hundred (100) vertical feet of a visually significant ridgeline and in the significant hillside areas depicted on General Plan community design map, are subject to design review, and new development is prohibited unless this precludes all reasonable economic use of the property. An exception to the ridgeline regulation may be granted if the decision-making body makes additional required findings, required pursuant to Chapter 14.12.   

Parking requirements: On streets less than twenty-six (26) feet wide, two additional on-site parking spaces shall be provided (not on the driveway apron) per unit; placed conveniently relative to the new dwelling unit. This requirement may be waived or reduced by the hearing body when the size or shape of the lot or the need for excessive grading or tree removal make the requirement infeasible

Lot Standards (Subdivisions): For new subdivision lots, the minimum lot sizes and widths are subject to the slope tables established under Chapter 15.34 of the subdivision ordinance.