Atherton Municipal Code Ch. 17.59 Regulations and Objective Standards for Development Projects Sought…

REGULATIONS AND OBJECTIVE STANDARDS FOR DEVELOPMENT PROJECTS SOUGHT PURSUANT TO GOVERNMENT CODE SECTION 65912.157 (SENATE BILL 79)

Sections:

• 17.59.010 Purpose.

• 17.59.020 Characteristics of the District.

• 17.59.030 Development Standards.

This chapter establishes development standards for multifamily uses on SB 79 qualifying lots that are located within one-quarter mile of the Menlo Park Caltrain station, which is a Tier 1 transit-oriented development stop, as defined in Government Code Section 65912.156(n). This chapter establishes development standards for new projects eligible under Government Code Section 65912.157 so as to establish a ministerial, “by-right” approval process pursuant to Government Code Section 65913.4. The town planner will review development applications against standards in this chapter to determine compliance with applicable zoning regulations. The Town will accept applications for eligible projects only upon the effective date of SB 79. (Ord. 678 § 4, 2026)

Projects sought under Government Code Section 65912.157 shall conform with the following requirements:

A. Projects are permitted to have a residential density of up to one hundred twenty dwelling units per acre and shall have minimum density of thirty dwelling units per acre.

B. The maximum average unit size shall be no greater than one thousand seven hundred fifty net square feet of habitable space per unit.

C. Projects shall meet statutory affordability requirements provided in Government Code Section 65912.157(6)(i) by allocating affordable units as follows:

1. Seven percent extremely low income;

   2. Ten percent very low income; or

   3. Thirteen percent lower income.

   4. Projects with ten or fewer units are exempt from statutory affordability requirements.

• D. Projects must also meet the Town’s inclusionary housing requirement as set forth in chapter 17.57. Affordable units provided to meet state law will count towards the Town’s requirement. (Ord. 678 § 4, 2026)

Multifamily projects sought under Government Code Section 65912.157 that comply with the standards in this chapter shall be considered ministerial (“by-right”) and shall be approved at staff level. However, this does not preclude other actions that require discretionary review (i.e., lot redesignations, variances, or special structure permits).

• A. Height. The maximum height for any building shall be seventy-five feet.

  1. Height measurement: see section 17.42.030.

  2. Dormers shall be in compliance with development standards in section 17.32.040(A)(4).

• B. Setbacks. A setback shall be required from all lot lines.

Minimum setback requirements are:

1. Front Yard. Any lot line that provides frontage on a public right-of-way shall be treated as a front lot line. The minimum setback shall be fifteen feet.

2. Side and Rear Yards. For lots with a gross lot area larger than one-half acre, the minimum side and rear yard setback shall be forty feet. For lots with a gross lot area of one-half acre or less, the minimum side and rear yard setback shall be twenty-five feet.

3. Accessory structures: as provided in chapter 17.40.

C. Floor Area Ratio. The maximum floor area ratio shall be three and one-half multiplied by the gross lot area, except for flag lots, which shall be calculated with the net lot area, as defined in chapter 17.60.

• D. Site Design. Site design requirements are as follows:

  1. Vehicle Access.

     • a. Vehicle access shall be located a minimum of one hundred feet from any street intersection. Where this standard cannot be met due to site constraints, access shall be located as far from the intersection as feasibly possible. In lieu of this requirement, the applicant may provide a traffic study that provides an alternative recommendation that the project implements.

b. Vehicle access shall conform to the requirements of the Fire Marshal with a minimum drive aisle width of twenty-six feet.

c. Any new driveway for a multifamily project shall be spaced a minimum distance of twenty-five feet from any existing driveway on an adjacent lot.

d. All driveways intersecting a public right-of-way shall provide a clear visibility area extending a minimum of fifteen feet inward from the lot line along the driveway and fifteen feet along the lot line. Within the clear visibility area, structures, landscaping, and other obstructions shall not exceed three feet in height. Trees are permitted within the clear visibility area provided the canopy maintains a minimum vertical clearance of six feet above ground level.

e. Vehicle entry gates, where provided, shall be set back a minimum of twenty feet from the edge of the improved public right-of-way. Gate controls shall be located to ensure that vehicles can fully clear the sidewalk and public right-of-way while accessing the gate.

2. Pedestrian Access.

a. All building and unit entries shall be connected to the public sidewalk and resident parking areas by a pedestrian pathway with a minimum clear width of five feet.

b. Pedestrian pathways are prohibited within ten feet of a lot line adjacent to a parcel with an R-1 zoning designation.

3. Streetscape and Frontage Design. A public sidewalk shall be provided along the full length of the lot frontage abutting any public right-of-way as illustrated in figure 17.59.030-1. Where the public right-of-way is insufficient to accommodate the required sidewalk width, the sidewalk shall extend into the front yard setback. The sidewalk shall conform with the following requirements:

• a. The sidewalk shall have a minimum width of eight feet and maintain a minimum clear pedestrian walkway width of five feet, as measured from the back of curb.

b. All non-impervious areas in the frontage between the sidewalk and the building shall be landscaped and maintained.

c. Sidewalk lighting shall be provided that is consistent with the Town’s guidelines and standards. Light fixtures shall be shielded and downlit and spaced at a maximum interval of sixty feet.

d. Street trees shall be provided along the sidewalk at a maximum interval of twenty feet on center and shall be a minimum twenty-four-inch box size at planting. At maturity, street trees shall have a minimum clear height of fourteen feet above the public right-of-way. If it is found that there are infrastructure conflicts or limited space by the Town Arborist and/or the Town Engineer, alternative planting may be required within the front setback. Tree species will be reviewed and approved by the Town Arborist. The property owner shall be responsible for maintaining street trees in compliance with chapter 12.10.

• e. The sidewalk shall be designed in compliance with ADA and Town standards.

f. A clear visibility area shall be maintained at all street corners, measured inward for a minimum of thirty feet from the lot line. Within the clear visibility area, structures, landscaping, and other obstructions shall not exceed three feet in height. Trees are permitted within the clear visibility area provided the canopy maintains a minimum vertical clearance of six feet above ground level.

g. Tree removals within the public right-of-way shall comply with the heritage tree protection requirements in chapter 8.10 and provide a replacement tree for each tree removed.

Figure 17.59.030-1. Streetscape Design

• E. Open Space Design. Open space design requirements are as follows:

  1. Minimum Open Space Area. Projects shall provide a minimum of ten percent of the net lot area as open space. Open space can be provided as common open space, private open space, or a combination.

  2. Common Open Space. Common open space shall comply with the following requirements:

• a. Setbacks from R-1 Lots. Common open space shall be provided at grade and set back a minimum of ten feet from any shared lot line with an adjacent lot with an R-1 zoning designation. Common open space designated for active recreation, including but not limited to accessory buildings and structures such as outdoor kitchens, pools, play areas, sport courts, and dog runs, shall be located no closer than forty feet to an R-1 lot line. Location of these features in the side or rear setback may be sought through a special structures permit.

b. Screening and Landscaping. Screening elements shall block direct horizontal sightlines into adjacent R-1 lots. Screening shall be provided along the edge of any at-grade common open space facing the R-1 property in the form of a landscape buffer that is at least fifteen feet in width, or a screening element (such as a wall, trellis, or similar) with a minimum height of six feet above the finished grade. A minimum of fifty percent of the common open space perimeter facing an R-1 lot shall include evergreen planting.

• c. Lighting. Lighting for common open space shall be shielded and downlit.

3. Private Open Space. Private open space shall comply with the following requirements:

   • a. Maximum Amount. Private open space shall not comprise more than forty percent of the open space requirement for a project.

   • b. Minimum Dimensions. Private open spaces shall have a minimum area of forty square feet and a minimum dimension of five feet in each direction.

   • c. All private open space shall be outdoors.

d. Balconies, patios, and decks shall not be allowed on walls that face an adjacent lot with an R-1 zoning designation, or on portions of any perimeter wall within twenty-five feet of the setback from the R-1 lot. See figure 17.59.030-2 (Balcony Placement).

Figure 17.59.030-2. Balcony Placement

• F. Landscaping.

1. All parts of the lot not covered by buildings or impervious surfaces shall be covered by landscape area. All landscape areas shall be maintained reasonably free of weeds, litter, and debris. All planting shall be maintained in a healthy growing condition and, whenever necessary, replaced with plant materials approved by the town arborist to provide continued conformance with approved plans. All new screening plantings shall be provided with a water-efficient automatic irrigation system to be installed at the time of planting. Landscape areas shall not interfere with heritage tree protection.

2. All shared lot lines with an adjacent lot with an R-1 zoning designation shall be screened according to the standards in chapter 17.50 and the standards in this section. Where standards conflict, the most restrictive standard shall apply.

• a. Prior to the final inspection or issuance of a certificate of occupancy (unless delay is authorized by the building official) all required landscape screening shall be installed in conformance with the approved plans. In the case of phased building construction, the town building official may permit phased installation of landscape screening. No other exception to this installation requirement shall be allowed, including any in-lieu fee or deposit.

b. All trees provided as landscape screening shall be at least thirty-four-inch box container size at the time of installation and shall reach a minimum height of twenty-five feet at maturity in accordance with the Sunset Western Garden book.

• c. All trees and shrubs shall be evergreen.

• d. If the lot line is screened with existing landscaping that is at least twelve feet tall and opaque, no new landscaping is required.

G. Façade Organization. Building façades shall be organized using a two-step system of vertical and horizontal articulation. Façades shall be divided vertically into a base, middle, and top to establish hierarchy between the ground floor and upper stories, and horizontally into modules and bays to reduce perceived building length and provide consistent architectural rhythm.

Minimum façade design requirements are as follows:

1. Vertical Façade Organization. All buildings that are four or more stories shall establish a base, middle, and top as defined below and illustrated in figure 17.59.030-3:

   • a. Base. The ground floor of a building. The floor-to-floor height of the base shall be equal to or greater than the floor-to-floor height of the middle and/or top. The base shall be visually differentiated from the middle through a continuous horizontal façade element, such as molding or trim, extending the full length of the building.

b. Middle. All floors located between the base and the top. The middle shall contain a number of floors greater than or equal to the number of floors in either the base or the top.

• c. Top. The roof and/or the uppermost floor of a building. Where the top includes a floor, the vertical height of that floor, measured exclusive of roof height, shall not exceed the vertical height of the base.

Figure 17.59.030-3. Vertical Façade Organization

2. Horizontal Façade Organization. Any building side greater than eighty feet in length shall be horizontally divided along the façade into a system of modules and bays. Modules are the primary divisions of a façade that establish overall rhythm and massing, while bays are secondary divisions within each module that organize windows, entries, and other openings.

• a. Module. A module is the primary division of a building façade. Any building side exceeding eighty feet in length shall provide two or more modules. Each module shall have a minimum width of forty feet and a maximum width of one hundred feet and shall include a minimum of one bay and a maximum of nine bays. Individual modules shall be differentiated by incorporating at least two of the following features:

  • i. A change in module width.

  • ii. A change in bay width between modules.

  • iii. A change in primary wall or finish material.

  • iv. A change in frontage type, as provided in subsection I of this section.

  • v. A change in window pattern.

  • vi. A change in eave or parapet height.

vii. A recess or projection that is at least two feet in depth.

b. Bays. A bay is a subdivision of a module and shall repeat the same material and opening pattern within its corresponding module. Each bay shall have a minimum width of six feet and a maximum width of forty feet. Bays are not required to be equal in width.

A bay shall meet all of the following requirements:

i. At least twenty-five percent of the bay façade area located above the ground floor shall consist of windows.

• ii. Entries and openings within a bay shall be vertically aligned on a common center axis.

• iii. No blank wall within a bay shall exceed twenty feet in length.

• iv. Within a bay, openings and materials can vary between a building’s base, middle, and top.

Figure 17.59.030-4. Horizontal Façade Organization

• H. Building Massing. Minimum building massing requirements are:

  1. Maximum Aggregate Façade Length. The aggregate length of all façade segments facing in a common direction shall not exceed one-hundred sixty feet per building, as measured wall to wall.

2. Massing Features. Massing features shall be provided along any building façade exceeding eighty feet in length in compliance with Table 17.59.030.H.2-1. Required massing features may be located anywhere along the façade; provided, that a minimum distance of thirty feet is maintained between features. Where two or more features are required, massing features may be combined or repeated on the same façade.

Table 17.59.030.H.2-1. Massing Features

Table 17.59.030.H.2-1. Massing Features

Building Length

Features Required

Allowable Massing Features

Massing features are allowed to encroach into a setback up to a maximum of five feet.

Figure 17.59.030-5. Massing Features

3. Allowable Massing Features. Allowable massing features are defined as and shall meet the following requirements:

   • a. Tower. A tower is a portion of a building that projects vertically above its roofline. A tower shall comply with all of the following requirements:

     • i. Width and Depth. Minimum of ten feet, maximum of thirty feet.

     • ii. Height. A tower may exceed the maximum building height for up to a maximum of ten feet.

iii. Projection or Recess. Provide a minimum three-foot projection or recess from the immediately adjacent façade. This shall not be counted as the recess or projection feature in subsection (H)(3)(c) of this section.

• iv. Bays. The tower includes at least one and a maximum of three bays.

• v. Ground-Level Entry. A common entry shall be provided at the base of the tower.

• vi. Street Corners. A tower located at a street corner shall provide openings on both street-facing façades to access a common building entry.

b. Step Back. A step back is a portion of the building above the ground floor that reduces the upper story footprint in comparison to the ground floor. A step back shall comply with all of the following requirements:

• i. Depth. Minimum depth of ten feet.

• ii. Length and Location. A minimum length of twenty feet, extending the full length of the corresponding module, and located above the building’s base.

c. Projection or Recess. A projection or recess is a portion of a building façade that extends outward from or is set back from the primary wall plane. A projection or recess shall comply with all of the following requirements:

• i. Depth. Minimum depth of three feet.

• ii. Location. Be located in a building’s middle, and can optionally extend through the base or top.

• iii. Balconies. May be included in the recess; however, the front of the balcony must be set back from the building façade a minimum of one foot.

iv. Bay Windows. May project into the front setback up to three feet if located on stories above the ground floor. Each bay window is limited to a maximum width of eight feet and must be separated from an adjacent bay window by two feet. The glass areas of each bay window must be at least fifty percent of the sum of the areas of the vertical surfaces of the bay window.

• I. Entries and Openings. Minimum entry and opening design requirements are:

  1. Resident Entries Facing R-1 Lots. No more than two resident entries shall be provided on any building façade facing an adjacent R-1 lot, except where additional entrances are required to comply with fire and life safety requirements in the California Building Code.

2. Primary Entries. A primary entry shall be provided to access one or more units from the exterior of a main building.

In addition to the primary entry requirement, a primary entry shall conform with at least one of the frontage typologies listed in standards in subsections (I)(2) through (I)(4) of this section. Frontage typologies can be combined and can encroach into the front setback up to a maximum of five feet.

3. Common Entry. A common entry is a large opening that leads directly into a lobby or common space on the ground floor. A common entry shall comply with the following standards. See figure 17.59.030-6 (Common Entry Requirements).

Table 17.59.030.I.2-1. Common Entry Requirements

Figure 17.59.030-6. Common Entry Requirements

4. Stoop. A stoop is a small, raised entry that shall conform with the following standards. See figure 17.59.030-7 (Stoop Requirements).

Table 17.59.030.I.3. Stoop Requirements

Weather protection shall be provided with a projection or recession for a minimum depth of twelve inches. A stoop shall provide direct access to no more than two units.

Figure 17.59.030-7. Stoop Requirements

5. Frontage Court. A frontage court is an open-air space on the building frontage with primary entries oriented to the courtyard interior. A forecourt shall conform with the following standards. See figure 17.59.030-8 (Frontage Court Requirements).

Figure 17.59.030-8. Frontage Court Requirements

6. Terrace. A terrace is an elevated area for pedestrian circulation along a building frontage that provides access to one or more primary entries. See figure 17.59.030-9 (Terrace Requirements).

Table 17.59.030.I.5. Terrace Requirements

Terrace stairs shall be spaced no more than twenty-five feet apart.

A terrace shall provide direct access to no more than four units.

Figure 17.59.030-9. Terrace Requirements

7. Minimum window detail requirements are:

a. Windows shall be recessed at least two inches from the exterior wall plane to the window glass. See figure 17.59.030-10 (Window Detail Requirements).

• b. Window sills shall project a minimum of two inches from the surrounding exterior wall plane. See figure 17.59.030-10 (Window Detail Requirements).

Figure 17.59.030-10. Window Detail Requirements

c. Any window facing an R-1 lot, located on the second floor or higher, shall provide translucent, but not transparent, glazing for any part of the window glass less than fifty-four inches above the finished floor. See figure 17.59.030-11 (Window Privacy).

Figure 17.59.030-11. Window Privacy

• d. Windows shall be vertically oriented and taller than they are wide.

• e. All privacy windows shall be translucent but not transparent; reflective glass is prohibited.

• J. Façade Material Requirements.

  1. Prohibited Materials. The following materials shall be prohibited on any main building façade:

     • a. An exterior insulation finishing system (EIFS).

     • b. Aluminum lap siding.

     • c. T1-11 siding.

     • d. Vinyl siding.

  2. Materials and Color. Building materials shall meet the following requirements:

     • a. Any building façade shall use no more than three colors and three materials; window trim and fascia are excluded from this limit.

     • b. Heavier façade materials shall be placed beneath lighter materials.

• c. Changes in building materials or color shall occur horizontally on the building façade, such as to differentiate a building base from a building middle, as per subsection (G)(1) of this section, or at the inside corners of a building façade. See figure 17.59.030-12 (Change in Material).

Figure 17.59.030-12. Change in Material

• K. Roof and Eave Details. Minimum roof and eave detail requirements are:

  1. Roof eaves may encroach into any yard not to exceed a maximum of four feet on the main building.

  2. Roof parapets, when included, shall be a minimum of three feet tall and may not exceed the maximum building height. Roof parapets shall be consistent in material and color with the main building.

  3. Any equipment placed on the rooftop of a building shall be screened entirely from view as seen from the finished grade.

• L. Site Lighting. Minimum site lighting requirements are:

  1. No exterior lighting element shall be placed above the height of eight feet above the ground plane unless to illuminate a private habitable outdoor area or is required by the California Building Code. All exterior lighting shall be directed downward and fully shielded to restrain light to a minimum thirty degrees below the horizontal plane of the light source. Lighting shall be arranged so that the light will not shine directly onto any adjacent lot.

  2. Up-lighting of trees and permanent lighting within trees is prohibited.

  3. Interior lighting of all common areas shall be controlled by motion detecting controls programed to turn off no more than five minutes after movement is no longer detected by the controlling device. Interior “common areas” are spaces used by multiple units generally for circulation purposes having exterior-facing windows.

• M. Accessory Buildings and Structures. Where standards in this section conflict with chapter 17.40, the most restrictive standard shall apply.

  1. Accessory Buildings. Accessory buildings shall not be allowed in the front setback. Accessory buildings in the side and rear setbacks shall be set back from the lot line for a minimum of ten feet, or a minimum of fifteen feet on a shared lot line with a lot with an R-1 zoning designation.

  2. Garages.

     • a. All garages shall be completely enclosed and include a lockable garage door.

     • b. Materials and colors on garages shall be consistent with the materials and colors utilized on the main building(s).

  3. Trash and Recycling Enclosures.

     • a. Trash disposal and recycling areas shall be within an enclosure and shown on the site plan. Trash shall be collected on the subject property.

     • b. Each enclosure shall screen trash and recycling receptacles from public view.

     • c. Trash and recycling enclosures shall be a minimum of six feet and a maximum of eight feet in height. The enclosure shall be constructed of solid wood or masonry painted the same color as the main building(s).

• d. Trash and recycling enclosures shall have a gate and a roof.

  • e. Trash and recycling enclosures are not permitted within any setback.

4. Mailboxes.

a. Mailboxes shall be clustered in a common centralized interior location that is part of or within twenty-five feet of a main building.

• b. Mailboxes shall be located outside of the public right-of-way.

• N. Parking. Parking requirements are:

  1. Vehicle Parking.

     • a. There is no minimum resident or guest parking requirement.

     • b. Total resident and guest parking shall not exceed one and one-quarter spaces per unit.

     • c. Total resident and guest parking can be increased to a maximum of two spaces per unit if all the resident and guest parking spaces are provided in a below-grade parking garage.

     • d. Parking areas shall not be located between the front of the building and the sidewalk.

     • e. Surface parking areas shall be set back a minimum distance of five feet from a side or rear lot line.

  2. Parking Garage Design.

     • a. No more than twenty-five percent of any ground floor façade shall be dedicated to garage openings.

b. Garaged parking that is above grade shall be screened from a public right-of-way with livable space that has a minimum depth of twenty feet. Livable space shall include any multifamily housing use that does not include vehicle parking.

• c. Partially sub-grade parking shall not have an exposed façade that exceeds five feet above grade and shall provide landscape screening with a minimum depth of ten feet along the entire façade length.

3. Bicycle Parking. Short-term bicycle parking shall be provided at a primary entry (Class II bicycle parking facility) that consists of racks that support the bicycle frame at two points and allow for the bicycle frame and one wheel to be locked to the rack with a U-lock.

Minimum bicycle parking requirements are:

• a. Resident bicycle parking shall be provided at a minimum rate of one bicycle parking space per every two dwelling units.

• b. Resident bicycle parking shall be covered within an interior storage room or with lockable enclosures that are permanently anchored.

• c. Bicycle parking facilities shall be located on the ground floor.

• d. Bicycle parking facilities shall be located within twenty-five feet of a public right-of-way.

• e. Bicycle parking that is placed below grade shall not be counted as floor area.

4. Vehicle Miles Travelled Analysis. Development proposals located in a high-VMT area shall include a VMT analysis that identifies travel demand management (TDM) measures and/or physical measures to reduce VMT impacts to less than significant. The VMT analysis shall use the City/County Association of Governments of San Mateo County (C/CAG) VMT Estimation Tool. (Ord. 678 § 4, 2026)