(a)   Public Facilities District [PF]

   The PF public facilities district is designed to accommodate governmental, public utility, educational, and community service or recreational facilities.

   (b)   Open Space District [OS]

   The purpose and intent of this district is to:

      (1)   protect the public health, safety, and welfare;

      (2)   protect and preserve open space land as a limited and valuable resource;

      (3)   permit the reasonable use of open space land, while at the same time preserving and protecting its inherent open space characteristics to assure its continued availability for the following: as agricultural land, scenic land, recreation land, conservation or natural resource land; for the containment of urban sprawl and the structuring of urban development; and for the retention of land in its natural or near-natural state, and to protect life and property in the community from the hazards of fire, flood, and seismic activity; and

      (4)   coordinate with and carry out federal, state, regional, county, and city open space plans.

   (c)   Agricultural Conservation [AC]

   The AC agricultural conservation district is intended to permit agricultural and compatible uses on property intended for preservation and retention essentially in its natural, farmed, or landscaped state.

(Ord. 4964 § 4 (part), 2007)

   As used in this chapter, unless otherwise apparent from the context, the following definitions shall apply:

   (a)   “Conservation or natural resource land” means land which possesses or encompasses conservation or natural resources.

   (b)   “Conservation or natural resource” includes, but is not necessarily limited to, streams, watersheds, groundwater recharge, soils, wildlife habitat, as defined in this section, special land forms, and natural vegetation.

   (c)   “Farmworker housing” means employee housing, as that term is defined in California Health and Safety Code Section 17008, for agricultural employees, as that term is defined in California Labor Code Section 1104.4.

   (d)   “Open space land” means any parcel or area of land essentially unimproved or in its natural state, and devoted to an open space use as defined in this section, and which is designated in the open space element for an open space use.

   (e)   “Open space district” means any area of land or water designated “OS” and subject to all of the terms and regulations of this chapter.

   (f)   “Open space use” means the use of land for:

      (1)   Public recreation;

      (2)   Enjoyment of scenic beauty;

      (3)   Conservation or use of natural resources;

      (4)   Production of food or fiber;

      (5)   Protection of persons and their artifacts (buildings, property, etc.);

      (6)   Containment and structuring of urban development.

   (g)   “Recreation land” means any area of land or water susceptible to recreational uses.

   (h)   “Scenic land” means any area of land or water that possesses scenic qualities worthy of preservation.

   (i)   “Wildlife habitat” means any area of land or water valuable or necessary to the preservation or enhancement of wildlife resources.

(Ord. 5646 § 7 (part), 2025: Ord. 5123 § 6 (part), 2011: Ord. 4964 § 4 (part), 2007)

   The specific regulations of this chapter and the additional regulations and procedures established by this title shall apply to all Special Purpose Districts.

(Ord. 4964 § 4 (part), 2007)

   Table 1 shows the permitted (P) and conditionally permitted (CUP) land uses for the Special Purpose Districts.

 

(Ord. 5656 § 8 (part), 2025: Ord. 5646 § 7 (part), 2025: Ord. 5505 § 2, 2020: Ord. 5490 § 7, 2020: Ord. 5412 § 18, 2017: Ord. 5134A § 4, 2011: Ord. 4964 § 4 (part), 2007: Ord. 5608 § 9, 2024)

   (a)   Development Standards. On Housing Element opportunity sites (City-owned parking lots): development standards are identified in Section 18.14.020.

 

   (b)   Open Space Impervious Coverage and Floor Area

      (1)   Residential Use

         The impervious coverage and floor area ratios shall be determined based on a sliding scale calculation. Table 3 provides the range of allowable percentages for the calculation. Allowable development for other site sizes between 1 and 10 acres shall be calculated on a prorated basis between the acreages shown in Table 3. Except that on Housing Element opportunity sites (City-owned parking lots), development standards are identified in Section 18.14.020.

 

 

         (A)   Bonus FAR

            (i)   The bonus FAR incentive is intended to encourage property owners to preserve and enhance the natural environment and agricultural uses in the OS district. For those property owners who agree to maintain or restore the vegetative conditions on their property to a natural state with appropriate native plantings or with certain agricultural crops, the designated floor area bonus for the development of the property shall be permitted. The minimum area that must be maintained in a natural or restored state is described in Section 18.28.050(b).

            (ii)   Areas to be set aside as “undisturbed” or “restored” shall include, but not be limited to: a) vegetation that has not been disturbed by development (construction, ornamental landscaping, farming, orchards, etc.); b) plantings with vegetation that is now considered native to the area, especially including drought-resistant and fire-resistant plantings; and c) retention or planting of edible crops or orchards with negligible grading and involving no removal of native vegetation. For restoration projects, the proposed landscape plans shall be reviewed and approved by the Planning Department. The Director of Planning shall develop and maintain a list of native plantings and acceptable restoration vegetation.

            (iii)   As a requirement of receiving bonus FAR, the property owner shall enter into a covenant that is recorded with the property and would apply to all future property owners assuring that the designated areas will remain in the approved vegetative condition; enforcement provisions acceptable to the City Attorney will be outlined in the covenant. To remove the landscape restrictions related to the bonus FAR, the site development shall be modified to reduce the FAR to meet the standard requirements. These modifications are subject to design review.

            (iv)   For projects approved with bonus FAR, the property owner shall be required to submit a follow-up landscape/arborist report verifying the site is in compliance with the approved plans, five years after the project’s final sign-off, as outlined in 18.28.070(d).

         (B)   Calculation of Floor Area Ratio

            (i)   Gross floor area shall be calculated based upon the same criteria as Low Density Residential zone districts, as specified in Definitions Section 18.04.030(65)(C) and (D), except as below.

            (ii)   Basements shall follow the same standards as the R-1 Single Family Residential district, except that in addition basement area shall count if any portion is constructed on a slope in excess of ten percent (10%).

   (2)   Non-Residential Use

      Where non-residential uses are proposed on a site, the impervious coverage shall be limited to 3.5% and the floor area ratio shall be limited to 5.0% of the site area. However, the City Council may, after recommendation from the Planning and Transportation Commission, allow increased impervious coverage and/or floor area through the Site and Design Review process, where Council finds that the use furthers the open space objectives of this chapter. In no case shall impervious cover or floor area ratio be allowed to exceed 10.0%.

   The following additional regulations shall apply in the PF district:

   (a)   Recycling Storage

   All new development, including approved modifications that add thirty percent or more floor area to existing uses, shall provide adequate and accessible interior areas or exterior enclosures for the storage of recyclable materials in appropriate containers. The design, construction and accessibility of recycling areas and enclosures shall be subject to approval by the architectural review board, in accordance with design guidelines adopted by that board and approved by the city council pursuant to Section 16.48.070.*

   (b)   Employee Shower Facilities

   Employee shower facilities shall be provided for any new building constructed or for any addition to or enlargement of any existing building as specified in Table 3.

 

 

   (c)   Landscaping of Yards

      (1)   All required interior yards (setbacks) abutting or opposite a residential district shall be planted and maintained as a landscaped screen.

      (2)   For sites abutting a residential district, a solid wall or fence between 5 and 8 ft in height shall be shall be constructed and maintained along the common site line.

   (d)   Transfer of Development Rights*

      (1)   The city council by resolution may, from time to time, designate one or more city-owned buildings that are Category 1 or Category 2 on the city's historic inventory and/or Category I, II, or III on the city's seismic hazards identification list as eligible to participate as “sender sites” in the Transfer of Development Rights program as provided in Chapter 18.18.

      (2)   Before any transferable development rights are offered for sale, the city manager shall establish, in writing, a public process using the city's formal bidding procedures to sell bonus floor area development rights from any sites so designated by the city council.

      (3)   Before formally soliciting the participation of other organizations or agencies in the rehabilitation of a city-owned historic building, the city should have a historic structures report prepared by a qualified expert in accordance with the standards and guidelines of the California State Office of Historic Preservation.

      (4)   Before concluding a sale of transferable development rights for any city building, the city shall comply with Section 18.18.080.

      (5)   The city manager shall establish and maintain a special fund into which all proceeds of the sale of transferable rights, and any interest thereon, shall be deposited. Upon receipt and entry into the accounting records for the fund such monies shall be considered committed to the rehabilitation of the city-owned building from which the development rights were sold, or to the rehabilitation of other city-owned buildings in the Historic Category 1 or 2 or Seismic Hazard Categories I, II, or III.

   (e)   Development Standards Exceptions

      The city council may in its discretion modify the development standards in Table 2 of Section 18.28.050 and setback lines established by a special setback map under Chapter 20.08 of Title 20, to achieve community objectives for the following facilities:

      (1)   Parking facilities, including appurtenant structures, within the Downtown and the California Avenue business district, where the parking facility is the principal use and is owned or leased, and operated or used, by the City of Palo Alto. "California Avenue business district" means that area bounded by the following streets in the City of Palo Alto: Grant Avenue to the south, El Camino Real to the west, College Avenue to the north, and Park Boulevard to the east.

      (2)   Essential services buildings as defined in Health and Safety Code section 16007, as amended, including appurtenant or ancillary structures.

      The exceptions shall be included in the review of the project through the applicable development review process.

(Ord. 5445 § 2, 2018: Ord. 5062 § 3, 2009: Ord. 4964 §§ 4 (part), 16, 2007)

   The following additional regulations shall apply in the OS district:

      Accessory Dwelling Units and Junior Accessory Dwelling Units are subject to the regulations set forth in Chapter 18.09.

      All sites in the OS district shall be subject to the Site Design and Review Combining District (D) as provided in Chapter 18.30(G) of the Zoning Ordinance, subject to the following modifications:

      (1)   Minor Site and Design Review: For minor projects (e.g., fences, landscape changes to an approved project, trash enclosures, accessory buildings 200 square feet or less, etc.), the review process shall follow the Minor Architectural Review (staff level) procedures as outlined in Section 18.77.070. To qualify as a minor project, the project shall have less than 10 cubic yards of excavation and or grading and be Categorically Exempt from the California Environmental Quality Act (CEQA).

      (2)   Major Site and Design Review: For all other projects not reviewed as Minor Site and Design Review, the project will be forwarded to the Planning and Transportation Commission for review and recommendation and then placed on the Council Consent agenda for final action, as prescribed for staff actions outlined in Section 18.77.060 (Standard Staff Review Process). Provided, however, that the following projects may be forwarded directly to the City Council Consent agenda by staff, without review by the Planning and Transportation Commission, where all of the following conditions apply:

         a.   The project is not a second dwelling unit; and

         b.   The project would comprise less than 1,000 square feet of floor area, less than 1,000 square feet of impervious cover, and less than 100 cubic yards of excavation and/or grading; and

         c.   The proposed floor area or impervious cover would not exceed 50% of the allowable for the site; and

         d.   The project and any prior projects within the prior five years would not cumulatively exceed these thresholds.

      (3)   Farmworker housing may be entitled to streamlined review pursuant to California Health and Safety Code Section 17021.8.

   (c)   Geological Soils Investigation and Report

      (1)   All applications for site and design approval shall be accompanied by a combined in-depth geologic and soils investigation and report prepared by a registered geologist certified by the state of California as an engineering geologist, and by a licensed civil engineer qualified in soil mechanics. Such report shall be based on surface, subsurface, and laboratory investigations and examinations and shall fully and clearly present:

         (A)   All pertinent data, interpretations, and evaluations;

         (B)   The significance of the data, interpretations, and evaluations with respect to the actual development or implementation of the intended land uses, and with respect to the effect upon future geological processes both on and off the site;

         (C)   Recommendations for any additional investigations that should be made. All costs and expenses incurred as a result of the requirements of this section, including the costs and expense of an independent review of the material submitted under this chapter by qualified persons retained by the city, shall be borne by the applicant.

      (2)   The requirement of subsection (1) may be waived by the city engineer for accessory facilities and landscaping where such improvements, in his opinion, would pose no potential hazard to life or property on the subject or surrounding properties.

   (d)   Landscaping

   The existing natural vegetation and land formations shall remain in a natural state unless modification is found to be necessary for a specific use allowed in this chapter through the site and design approval procedure. Reduction or elimination of fire hazards will be required where heavy concentrations of flammable vegetation occur. Landscaping as may be necessary and required shall be consistent with the purpose of this chapter.

      (1)   Landscaping shall be designed and installed consistent with the requirements and guidelines of Section 18.40.130 (Landscaping) of the Zoning Ordinance, and in particular with subsection 18.40.130(c) regarding landscaping in Natural Areas, as well as with the relevant Comprehensive Plan policies outlined in subsection (o) below. Exceptions to tree removal restrictions may be made for invasive species such as eucalyptus trees.

      (2)   A follow-up arborist and/or landscape report shall be required five years after the final sign-off of the project completion. This report shall evaluate the health of trees and significant landscape that were required for screen planting or and/or were designated as protected plantings on the approved plans for the project. The specifications of the report shall be provided in the conditions of approval of the project. This requirement also applies to sites that receive bonus floor area ratio (FAR) for maintaining specific percentages of the site as undisturbed native or restored. Any subsequent owner(s) shall also be obligated to replace any trees that die with trees of the same size and species stated on the approved planning and building permit plans.

   (e)   Fencing Restriction

   No barbed wire, or similar fencing having a cutting edge, may be installed except:

      (1)   To protect a vegetative community or wildlife habitat until it is fully established, subject to the imposition of reasonable time limits through site and design review pursuant to Chapter 18.30; and

      (2)   To enclose utility facilities, including, but not limited to, water or sewage pumps, storage tanks, and wells.

   (f)   Trash Enclosures

   Trash/recycle enclosures shall be permitted, with staff-level design review, within the front setback, including Special Setbacks, providing the enclosure is not more than six (6) feet tall, is covered, is fitted with self closing gates, and is screened. The access to the enclosure shall not be located on the side facing the street. The design of the enclosure shall be the minimum size needed to accomplish the purpose of enclosing and screening the containers.

   (g)   Tree Removal

   Removal of live trees shall be permitted only as provided in Title 8.

   (h)   Access to Remote Areas

   Roads, tracks, driveways, trails, or runways for automobiles, trucks, buses, or motorcycles or other wheeled vehicles shall not be developed except upon the securing of site and design approval. No such approval shall be granted except upon finding that the purpose for which the roads, tracks, driveways, trails, or runways are proposed is essential for the establishment or maintenance of a use which is expressly permitted in this chapter and that the design and location of the proposed roads, tracks, driveways, trails, or runways will be compatible with the terrain. The use of all roads, tracks, driveways, trails, or runways existing at the time of the adoption of this chapter which are nonconforming or have been established without proper approvals shall be terminated and shall be returned to natural terrain unless given approval in accordance with the regulations set forth in this chapter.

   (i)   Grading

   No grading for which a grading permit is required shall be authorized except upon the securing of site and design approval. No such approval shall be granted except upon a finding that the purpose for which the grading is proposed is essential for the establishment or maintenance of a use which is expressly permitted in this chapter and that the design, scope, and location of the grading proposed will be compatible with adjacent areas and will result in the least disturbance of the terrain and natural land features. All grading for which no permits or approvals are required shall be subject to the provisions set forth in this chapter.

   (j)   Soil Erosion and Land Management

   No site and design plan shall be approved unless it includes soil erosion and sediment control measures in accordance with any adopted procedures, technical standards, and specifications of the planning commission. No approval will be granted unless all needed erosion control measures have been completed or substantially provided for in accordance with said standards and specifications. The applicant shall bear the final responsibility for the installation and construction of all required erosion control measures according to the provisions of said standards and specifications.

   (k)   Subdivision

   All divisions of land into four or more parcels shall be designed on the cluster principle and shall be designed to minimize roads; to minimize cut, fill, and grading operations; to locate development in less rather than more conspicuous areas; and to achieve the purpose of this chapter.

   (l)   Substandard Lots

   Any parcel of land not meeting the area or dimension requirements of this chapter is a lawful building site if such parcel was a lawful building site on July 5, 1972. All other requirements of this chapter shall apply to any such parcel.

   (m)   Impervious Coverage

   The intent of limiting impervious cover is to minimize runoff, enhance infiltration to the soil, and provide a semi-rural appearance compatible with the OS district. Impervious coverage allowances are prescribed in Section 18.28.050(b) and shall be calculated as outlined below to include all building coverage, plus paved surfaces including but not limited to driveways, parking areas, sports or tennis courts, swimming pools, patios or decks, subject to exceptions and provisions as follows:

      (1)   All paved surfaces shall be classified as 100%, 75%, 50%, or 25% impervious, based upon the material that is to be used and the proposed design and installation. Determinations shall be made by the Planning Director based on permeability information provided by the applicant, and the Director may consult with the Public Works Department when necessary to determine the extent of the permeability. The applicant may provide information in the soils report to outline the baseline permeability of the specific areas proposed for coverage, and the baseline may be considered in determining the permeability of the material.

      (2)   A primary driveway composed of gravel or decomposed granite shall not be counted as impervious up to a width of 20 feet, where approved for use by the Public Works and Fire Departments.

      (3)   The portions of a primary driveway located in the 200 scenic setback shall be designed to have a natural appearance and shall not be counted as impervious up to a width of 20 feet (assuming the primary residence is located beyond the 200 setback).

      (4)   A primary driveway is one that extends from the nearest access road to the garage or carport providing the required parking for the main residence.

      (5)   The proposed pervious paving materials for the primary driveway shall only be permitted if acceptable to the Palo Alto Fire Department.

      (6)   The water surface area for in-ground pools and hot tubs shall not be counted as impervious. The Fire Department may require additional specifications for the pool in order to utilize the water more effectively for emergency response.

      (7)   The areas excluded from impervious coverage pursuant to approvals granted prior to July 1, 2007 shall remain excluded from impervious coverage calculations, unless the surfacing material is altered to a less permeable material.

   (n)   Light and Glare

   Exterior lighting should be low-intensity and shielded from view so it is not directly visible from off-site. The light emitted from skylights shall be minimal during the night hours. Utilizing treatments such as translucent glass, shading systems, and interior light placement can reduce the night glare. Skylights shall not use white glass.

   (o)   Story Poles and Other Visual Review Aids

   Story poles (with associated taping or flagging) shall be erected for projects involving new residences or other structures, or for substantial additions to new residences, for the purpose of providing a better understanding of the visual impacts of a proposal in the OS district. Story poles shall accurately outline the perimeter and key and highest rooflines of the proposed structure(s) and shall be durable and sturdy enough to be visible from distant views. Story poles shall be constructed to the satisfaction of the director prior to notice of a hearing and shall remain in place through the public hearing date. Erection of story poles prior to public hearing notice may be required by the director to allow for staff and neighbors to view the project. Other aids, such as taping the perimeter of other development (structures, pools, sport courts, etc.) on the site and identifying trees to be removed, may also be required by the director. Story poles shall be removed upon final action on a project or upon the direction of the director.

   (p)   Open Space Review Criteria

   In addition to the above provisions and development standards in Table 2, the following criteria shall be considered in the Site and Design review of all development of land in the OS district, as outlined in the Conservation Element of the Comprehensive Plan:

      (1)   The development should not be visually intrusive from public roadways and public parklands. As much as possible, development should be sited so it is hidden from view.

      (2)   Development should be located away from hilltops and designed to not extend above the nearest ridge line.

      (3)   Site and structure design should take into consideration impacts on privacy and views of neighboring property.

      (4)   Development should be clustered, or closely grouped, in relation to the area surrounding it to make it less conspicuous, minimize access roads, and reduce fragmentation of natural habitats.

      (5)   Built forms and landscape forms should mimic the natural topography. Building lines should follow the lines of the terrain, and trees and bushes should appear natural from a distance.

      (6)   Existing trees with a circumference of 37.5 inches, measured 4.5 feet above the ground level, should be preserved and integrated into the site design. Existing vegetation should be retained as much as possible.

      (7)   Cut is encouraged when it is necessary for geotechnical stability and to enable the development to blend into the natural topography. Fill is generally discouraged and should never be distributed within the driplines of existing trees. Locate development to minimize the need for grading.

      (8)   To reduce the need for cut and fill and to reduce potential runoff, large, flat expanses of impervious surfaces should be avoided.

      (9)   Buildings should use natural materials and earthtone or subdued colors.

      (10)   Landscaping should be native species that require little or no irrigation. Immediately adjacent to structures, fire retardant plants should be used as a fire prevention technique.

      (11)   Exterior lighting should be low-intensity and shielded from view so it is not directly visible from off-site.

      (12)   Access roads should be of a rural rather than urban character. (Standard curb, gutter, and concrete sidewalk are usually inconsistent with the foothills environment.)

   (q)   Standard Conditions of Approval

   The director shall maintain a list of standard project conditions for projects in the OS district that reflect the intent of the OS criteria. Conditions may address, but are not limited to, landscaping, tree protection, planting, and maintenance, lighting, roofing materials, grading, construction staging, and fire protection.

   (r)   Development Standards Exception

   Pursuant to a 1978 Settlement Agreement, nine designated lots less than 10 acres in size, located on page 54, book 182 of the Assessor’s Parcel Maps (182-54-xxx) are entitled to be developed as if they complied with the 10 acre minimum lot size for the OS zone. Owners of these nine lots may choose to comply with the parameters of the 1978 Agreement or the standard development regulations as described in this Chapter. A site shall utilize either the 1978 Agreement standards or the regulations described in this Chapter, but cannot use both.

(Ord. 5656 § 8 (part), 2025: Ord. 5646 § 7 (part), 2025: Ord. 5432 § 9, 2018: Ord. 5412 § 19, 2017: Ord. 5062 § 4, 2009: Ord. 4964 § 4 (part), 2007)

   The following additional regulations shall apply in the AC district:

   All sites in the AC district shall be subject to the Site Design and Review Combining District (D) regulations as provided in Chapter 18.30(G), except that farmworker housing may be entitled to streamlined review pursuant to California Health and Safety Code Section 17021.8.

   (b)   Location of Agricultural Facilities

   Barns, stables, sheds, chicken houses, and other similar facilities for the shelter and feeding of animals, exclusive of domestic household pets, shall be located a minimum of 40 feet from any site line.

(Ord. 5646 § 7 (part), 2025: Ord. 5062 § 5, 2009: Ord. 4964 § 4 (part), 2007)

   Off-street parking and loading facilities shall be required for all permitted and conditional uses in accord with Chapter 18.40. All parking and loading facilities on any site, whether required as minimums or optionally provided in addition to minimum requirements, shall comply with the regulations and the design standards established by Chapter 18.42. In addition, parking facilities shall be subject to the following regulations:

   (a)   PF District

   In the PF district, no required parking space shall be located in the first 10 feet adjoining the street property line of any required yard. The city council may waive this requirement for eligible parking facilities and essential services buildings through the process provided in Section 18.28.060(e).

   (b)   OS District

      (1)   In the OS district, no parking space shall be located in a required front or side yard or in a special setback.

      (2)   Vehicle parking, other than the four required spaces, may be allowed in the 200' Special Setback if located at least 100' from the affected property line, as approved through the Site and Design review process. A lesser setback, with a minimum of 50', may be considered if the 100' setback is determined by the Planning Director as infeasible based on the site constraints. These additional spaces shall be screened from public views.

   (c)   AC District

   In the AC district, no required parking space shall be located in a required front yard or required street side yard.

(Ord. 5445 § 3, 2018: Ord. 5062 § 6, 2009: Ord. 4964 § 4 (part), 2007)