Chapter 2.30 — URBAN RESIDENTIAL BASE DISTRICTS

The purpose of this chapter is to define allowable land uses and property development standards for the urban residential base districts, which include the R1 "One-Family Residence," R1E "One-Family Residence—Estate," RHS "Urban Hillside Residential," R1S "Low-Density Campus Residential," R3S "Medium-Density Campus Residential," R2 "Two-Family Residence," and R3 "Multi-Family Residential" districts. The overall purposes of the urban residential base districts are to provide for appropriate uses in the unincorporated areas of the County that are within the urban service areas of cities and to regulate the type and intensity of development in these areas in a manner consistent with the general plan of the applicable city. The further specific purposes of each of the urban residential base districts are described below.

A.

R1 One Family Residence. The purpose of the One-Family Residence district, also known as the R1 district, is to provide for single-family dwellings, and for the orderly and efficient arrangement of dwellings, yards, accessory buildings, and other residential site improvements.

B.

R1E One Family Residence—Estate. The purpose of the One-Family Residence—Estate district, also known as the R1E district, is to provide for low-density single-family dwellings, and for the orderly and efficient arrangement of dwellings, yards, accessory buildings, and other residential site improvements.

C.

RHS Urban Hillside Residential. The purpose of the Urban Hillside Residential district, also known as the RHS district, is to provide for low-density residential development and limited agricultural uses on foothill lands adjacent to incorporated cities. RHS districts include areas that are particularly vulnerable to natural hazards and environmental degradation. Development density shall be determined by slope-density formulas that consider availability of public water and sewer, and by the severity of geologic and natural hazards. Note that Section 2.30.040 applies to this district.

D.

R1S Low-Density Campus Residential. The purpose of the Low-Density Campus Residential district, also known as the R1S district, is to provide for urban low-density housing (up to eight units per acre) on the lands of Stanford University, and to provide for limited neighborhood-supporting nonresidential uses. This

designation implements the specific land use policies for low-density housing prescribed by the 2000 Stanford Community Plan by encouraging more compact and efficient urban development.

E.

R3S Medium-Density Campus Residential. The purpose of the Medium-Density Campus Residential district, also known as the R3S district, is to provide for urban medium-density housing on the lands of Stanford University, and to provide for limited neighborhood-supporting nonresidential uses. This designation implements the specific land use policies for the medium-density housing prescribed by the 2000 Stanford Community Plan.

F.

R2 Two-Family Residence. The purpose of the Two-Family Residence district, also known as the R2 district, is to provide for one- and two-family dwelling units, and for the orderly and efficient arrangement of dwellings, yards, accessory buildings, and other residential site improvements.

G.

R3 Multi-Family Residential. The purpose of the Multi-Family Residential district, also known as the R3 district, is to provide space for multiple family residential development commonly found in an urban environment. The R3 district is intended for intensive residential uses at readily accessible urban locations.

The following tables, Tables 2.30-1 and 2.30-2, specify the allowable land uses for the urban residential base districts, listed by use classification as defined in Chapter 2.10. The regulations for each district are established by letter designations as follows:

Supplemental regulations for the establishment and conduct of a use are referenced in the "Supplemental Regulations" column of the tables. Use classifications not listed in the table are prohibited in the urban residential base districts.

TABLE 2.30-1. RESIDENTIAL USES IN URBAN RESIDENTIAL BASE DISTRICTS

NOTES:

1.

Single-family dwellings, including certain additions, and duplexes, may be subject to the building site approval provisions of Section C12-300 et seq. of the County Ordinance Code.

In R1S districts, ASA is required for new single-family residences on lots smaller than 10,890 square feet (0.25 acre), excluding housing development pursuant to Section 65852.21 of the California Government Code. ASA is not required for additions or remodels of existing dwellings.

3.

In R3S districts, accessory structures not meeting the criteria of § 4.20.020 may be allowed subject to ASA.

4.

Facilities qualifying as "Large Family Day Care Homes," serving between seven and 14 children, are subject to an administrative permit, per the provisions of Division B24 of the County Ordinance Code.

5.

Not to exceed two dogs and five cats over four months of age on parcels less than five acres, or three dogs and five cats over four months of age on parcels five acres or more, unless the required permit is secured pursuant to Division B31 of the County Ordinance Code.

6.

Small animals—Limited. Not to exceed a total of 12 of any of the following small animals: rabbits, guinea pigs, chicken and fowl, and similar species as approved by the Zoning Administrator. Roosters, peafowl, guinea fowl, geese or quacking ducks are not allowed.

7.

Horses. Minimum lot size for the keeping of horses in urban residential districts is one-half acre. Not to exceed two horses per acre.

8.

Expanded home occupations are permitted on lots of one acre or larger. See § 4.10.180 for other criteria.

9.

Owner-occupancy of one unit is required in any single-family residence that contains a junior accessory dwelling unit. The owner may reside in either the single-family residence or the junior accessory dwelling unit. Owner-occupancy shall not be required if the owner is a governmental agency, land trust, or housing organization.

10.

No more than four total dwelling units may be permitted on a parcel pursuant to the Urban Primary Unit use classification; however, all parcels resulting from an urban lot split pursuant to Section C12-44 shall have no more than two total dwelling units per parcel.

11.

Development on parcels with the -os designator is restricted to multi-family housing and limited mixed-use residential development, shall conform with the provisions of Chapter 3.75, and is allowable by ASA or planning clearance pursuant to § 3.75.040.

TABLE 2.30-2. NON-RESIDENTIAL USE CLASSIFICATIONS IN URBAN

RESIDENTIAL BASE DISTRICTS

NOTES:

1.

On lots two and one-half acres or larger in RHS districts, all agricultural uses permitted in HS districts as a matter of right (see Table 2.20-2) shall be allowed.

2.

Commercial and service uses permitted in R1S, R3S and R3 districts shall be limited in scale and in their service market to primarily serve the residents of the subject residential development. For residential support uses in R1S and R3S districts applicable to Stanford University lands, a business plan is required demonstrating that a preponderance of customers will be Stanford residents or employees.

3.

Facilities qualifying as "Large-Family Day-Care Homes," serving between seven and 14 children, are subject to an administrative permit, per the provisions of Division B24 of the County Ordinance Code.

4.

Utility structures and facilities may be exempt from local zoning regulations if they are established by a government agency. There may also be federal or state laws that provide exemptions for certain types of

utilities.

5.

Wireless telecommunications facilities are exempt from the development standards listed in Table 2.30-3.

6.

Established Religious Institutions and Nonprofit Institutions may include Emergency Shelters: Small-Scale as an ancillary use by right.

7.

In R3 zoning districts, any use that involves the sale or onsite consumption of alcoholic beverages shall be subject to a use permit.

(Ord. No. NS-1200.310, § 3, 5-20-03; Ord. No. NS-1200.317, § 5, 6-8-04; Ord. No. NS-1200.318, § 4, 3-2806; Ord. No. NS-1200.324, § 5, 5-5-09; Ord. No. NS-1200.327, § 7, 2-9-10; Ord. No. NS-1200.335, § 4, 124-12; Ord. No. NS-1200.337, § 5, 12-18-12; Ord. No. NS-1200.345, § 5, 6-10-14; Ord. No. NS-1200.348, § 1, 10-21-14; Ord. No. NS-1200.352, § 2, 9-29-15; Ord. No. NS-1200.354, § 3, 9-29-15; Ord. No. NS1200.360, § 3, 5-23-17; Ord. No. NS-1200.366, § 3, 5-1-18; Ord. No. NS-1200.371, § 4, 3-10-20; Ord. No. NS-1200.382, § 1, 5-24-22; Ord. No. NS-1200.383, § 3, 1-24-23; Ord. No. NS-1200.384, § 4, 12-12-23)

§ 2.30.030. - Development standards.

A.

Standards. Table 2.30-3 establishes property development standards for the urban residential base districts. A "-" indicates there is no applicable standard or requirement.

TABLE 2.30-3. URBAN RESIDENTIAL BASE DISTRICTS: PROPERTY DEVELOPMENT STANDARDS

NOTES:

1.

Development density for all housing types in R1S districts shall not exceed eight units per net acre. For the purposes of this provision, net acreage shall exclude street rights-of-way, but shall include driveways and other common access ways.

2.

Development density for all housing types in R3S districts shall be no less than eight units per net acre and no more than 15 units per net acre. For the purposes of this provision, net acreage shall exclude street rights-of-way, but shall include driveways and other common access ways.

3.

Development density in R3 districts shall conform to the density allowed by the applicable city general plan.

4.

In R3S districts, setbacks and maximum height for applications subject to Architecture and Site Approval (ASA) may be modified by the Zoning Administrator with proper justification to (a) promote quality design and functionality, (b) to assure adequate buffering and compatibility with adjacent land use and development, and (c) for consistency with the general purposes of ASA.

5.

In R1S districts, side and rear setbacks for single-family and two-family dwellings shall be as indicated in the table. For multi-family development subject to Architecture and Site Approval (ASA), side and rear

setbacks may be modified by the Zoning Administrator with proper justification to (a) promote quality design and functionality, (b) to assure adequate buffering and compatibility with adjacent land use and development, and (c) for consistency with the general purposes of ASA.

6.

For permitted non-residential uses, setbacks and height limits for applications subject to Architecture and Site Approval (ASA) may be modified by the Zoning Administrator with proper justification to (a) promote quality design and functionality, (b) to assure adequate buffering and compatibility with adjacent land use and development, and (c) for consistency with the general purposes of ASA.

7.

Setback requirements of applicable lot-size combining districts (§ 3.10.030) shall supersede the setbacks provided for base districts.

8.

Development on parcels with the -os designator is restricted to multi-family housing and limited mixed-use residential development, shall conform with the provisions of Chapter 3.75, and is exempt from the development standards in this table.

B.

Flag lots: Height restriction. On any flag lot of less than 20,000 square feet, the maximum height of dwellings shall be 21 feet and shall not include more than one story.

C.

Measurement. Standards shown in Table 2.30-3 are subject to the following rules of measurement:

1.

Where a lot abuts a road, setbacks from that road shall be measured from the edge of the ultimate right-ofway (see "setback" definition in § 1.30.030);

2.

Setbacks from all property lines not abutting a street shall be measured from the property line unless otherwise specified; and

3.

Height shall be measured according to the provisions of Chapter 1.30: Definitions: General Terms.

4.

Development density in R1S, R3S and R3 districts shall be calculated over the project area, which, excepting existing or new street rights-of-way, includes the entire area of any lot or assemblage of

contiguous lots upon which development or redevelopment is proposed, and for which one development application is submitted.

Any portions of the project area designated as open space by the applicable subdivision or ASA conditions shall be enforceably restricted to prevent increased density of development beyond that allowed by the zoning ordinance.

5.

Precision of numbers for the purposes of measurement and calculation shall be as stipulated in § 1.20.030: Precision of Numbers/Rounding.

(Ord. No. NS-1200.317, § 6, 6-8-04; Ord. No. NS-1200.332, § 2, 11-22-11; Ord. No. NS-1200.359, § 2, 126-16; Ord. No. NS-1200.384, § 5, 12-12-23)

Table 2.30-4 describes the required minimum land area per dwelling unit, or density of development allowed, as well as the minimum parcel sizes, for the RHS district, based on the availability of public water and sewer. Density of development may be further restricted based upon site-specific characteristics of proposed lots and building sites, including slope, geologic stability, drainage, and other factors.

TABLE 2.30-4. LOT SIZE/SLOPE-DENSITY FORMULAS IN RHS

NOTES:

1.

The variable "S" represents the average slope of the entire property that is the subject of the application. Average slope is determined according to the formula S = (0.00229 × IL)/A, where

I is the contour interval in feet;

L is the combined length of contour lines in scale feet;

A is the gross area in acres of the subject lot or area of land; and,

S is the average slope expressed as a percentage.

The maximum number of lots or dwelling units allowed is determined by dividing the gross land area by the minimum land area per dwelling unit and rounding down to the nearest whole number.

2.

Where the average slope of the parcel is less than ten percent, the land area per dwelling unit shall be equal to the lesser value in the lot area range. Where the average slope of the parcel is greater than 50 percent, the land area per dwelling unit shall be equal to the upper value of the lot area range.

3.

Minimum parcel size requirements are expressed in gross acres and may be waived through the approval of a cluster permit issued in conformance with applicable General Plan policies and the cluster permit procedures of Chapter 5.45 of this ordinance.

4.

Permanent dedication of open space and development rights shall be provided as necessary and appropriate to ensure that the maximum density of development (total number of lots) does not exceed that which is permitted by the applicable slope-density formula.