Atherton Municipal Code – SB 79 Ordinance (Administrative Draft) – February 2026
Attachment 4
Draft Ordinance No.
AN ORDINANCE OF THE CITY COUNCIL OF THE TOWN OF ATHERTON TO ADD CHAPTER 17.59 OF THE ATHERTON MUNICIPAL CODE, AND TO AMEND CHAPTER
17.60 OF THE ATHERTON MUNICIPAL CODE
WHEREAS, The State of California legislature passed Senate Bill 79, that necessitates development standards provided in a new Chapter of the Atherton Municipal Code; and WHEREAS, the Town of Atherton seeks to remain in compliance with State Regulations; and WHEREAS, the Planning Commission held a duly noticed public hearing as prescribed by law to consider the addition of Chapter 17.59 and amendments to Chapter 17.60 of the Atherton Municipal Code at the regular January 28, 2026 meeting to conform to state requirements and provide greater clarity in current language; and
WHEREAS, the Planning Commission recommended that the City Council add Chapter 17.59 and amend Chapter 17.60 of the Atherton Municipal Code at the regular January 28, 2026 meeting; and WHEREAS, on February, 18 2026, the City Council held a duly noticed public hearing as prescribed by law to consider the addition of Chapter 17.59 and amendments to Chapter 17.60 of the Atherton Municipal Code, receive public comment, and voted to continue to a second reading; and
WHEREAS, on March 18, 2026, the City Council held a duly noticed public hearing as prescribed by law to consider the second reading of the addition of Chapter 17.59 and amendments to Chapter 17.60 of the Atherton Municipal Code, and receive public comment; and
WHEREAS, the City Council finds that the addition of Chapter 17.59 and amendments to Chapter 17.60, are in conformance with the General Plan, particularly the following Goal, Objectives, Policies and Program:
Housing Element Goal 3.710 Facilitate the private development of housing to meet the above moderate income housing need identified for
Atherton.
Housing Element Objective 3.711 Realize the construction of approximately 150 net new housing units in the above-moderate income category in
Atherton from 2023-2031.
Housing Element Policy 3.712 Within the limitations of the private housing market the Town shall work with private developers to encourage
new housing development.
Atherton Municipal Code – SB 79 Ordinance (Administrative Draft) – February 2026
Housing Element Goal 3.760 Encourage special consideration to the maintenance and expansion of housing opportunities for handicapped and
low- and moderate-income homeless persons.
Housing Element Objective 3.761 B. Support the conservation and development of affordable housing for citizens of modest means.
Housing Element Goal 3.770 Meet the needs of seniors, in light of the pending growth of this population in San Mateo County
Housing Element Policy 3.772 B. Support the conservation and development of affordable housing for seniors with lower incomes.
NOW, THEREFORE, BE IT RESOLVED, that the City Council hereby adopts an ordinance to add Chapter 17.59 and to amend Chapter 17.60 of the Atherton Municipal Code based on the findings, supported by substantial evidence in the record, that:
The City Council of the Town of Atherton does hereby ordain as follows:
SECTION 1. RECITALS. The recitals set forth above are true and correct and are hereby incorporated herein by this reference as if fully set forth in their entirety.
SECTION 2. FINDINGS. In accordance with all requirements Atherton Municipal Code Section
17.18.040, the City Council hereby finds that the proposed amendments are consistent with the goals, policies, and implementation of the Atherton General Plan.
SECTION 3. COMPLIANCE WITH CEQA. The proposed Zoning Code Amendments have been reviewed with respect to applicability of the California Environmental Quality Act ("CEQA") and the State CEQA Guidelines (California Code of Regulations, Title 14, Sections 15000 et seq.).
SECTION 4. ADOPTION OF ZONING CODE AMENDMENTS. The City Council of the Town of Atherton hereby adopts Chapter 17.59 and amendments to Chapter 17.60 of the Atherton Municipal Code as follows:
Chapter 17.59
REGULATIONS AND OBJETIVE STANDARDS FOR DEVELOPMENT
PROJECTS SOUGHT PURSUANT TO GOVERNMENT CODE SECTION
65912.157
(Senate Bill 79)
17.59.010 Purpose.
This chapter establishes development standards for multifamily uses on SB 79 qualifying lots that are located within one-quarter (1/4) 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 sought under Government Code Section 65912.157 so as to establish a ministerial, “by-right”, approval process pursuant to Atherton Municipal Code – SB 79 Ordinance (Administrative Draft) – February 2026
Government Code Section 65913.4. The town planner will review development applications against standards in this chapter to determine compliance with applicable zoning regulations.
17.59.020 Characteristics of the District.
Projects sought under Government Code Section 65912.157 shall conform with the following requirements:
1. Projects are permitted to have a residential density of up to one hundred and twenty (120) dwelling units per acre and shall have minimum density of thirty (30) dwelling units per acre.
2. The maximum average unit size shall be no greater than one thousand seven hundred and fifty (1,750) net square feet of habitable space per unit.
3. Projects shall meet statutory affordability requirements provided in Government Code Section 65912.157(6)(i) by allocating affordable units as follows:
a. Seven (7) percent extremely low income,
b. Ten (10) percent very low income, or
c. Thirteen (13) percent lower income.
d. Projects with ten (10) or fewer units are exempt from statutory affordability requirements.
17.59.030 Development Standards.
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 (75) feet.
1. Height measurement: see chapter 17.42.030.
2. Dormers shall be in compliance with development standards in chapter 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 (15) feet.
Atherton Municipal Code – SB 79 Ordinance (Administrative Draft) – February 2026
2. Side and Rear Yards. For lots with a gross lot area larger than one-half (0.5) acre, the minimum side and rear yard setback shall be forty (40) feet. For lots with a gross lot area of one-half (0.5) acre or less, the minimum side and rear yard setback shall be twentyfive (25) 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 (3.5) 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 (100) 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 (26) feet.
c. Any new driveway for a multifamily project shall be spaced a minimum distance of twenty-five (25) 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 (15) feet inward from the lot line along the driveway and fifteen (15) feet along the lot line. Within the clear visibility area, structures, landscaping, and other obstructions shall not exceed three (3) feet in height. Trees are permitted within the clear visibility area provided the canopy maintains a minimum vertical clearance of six (6) feet above ground level. e. Vehicle entry gates, where provided, shall be set back a minimum of twenty (20) 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 (5) feet. b. Pedestrian pathways are prohibited within ten (10) feet of a lot line adjacent to a parcel with an R-1 zoning designation.
Atherton Municipal Code – SB 79 Ordinance (Administrative Draft) – February 2026
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 paved width of eight (8) feet and maintain a minimum clear pedestrian walkway width of five (5) 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 (60) feet.
d. Street trees shall be provided along the sidewalk at a maximum interval of twenty (20) feet on center and shall be a minimum 24-inch box size at planting. At maturity, street trees shall have a minimum clear height of fourteen (14) 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 (30) feet from the lot line. Within the clear visibility area, structures, landscaping, and other obstructions shall not exceed three (3) feet in height. Trees are permitted within the clear visibility area provided the canopy maintains a minimum vertical clearance of six (6) 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.
Atherton Municipal Code – SB 79 Ordinance (Administrative Draft) – February 2026
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 (10) 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 set back a minimum of ten (10) feet from any shared lot line with an adjacent lot with an R-1 zoning designation.
No common open space designated for active recreation (play areas, sport courts, dog runs) shall be located within forty (40) feet of an R-1 lot line. Common open space located within sixty (60) feet of an R-1 lot line shall be at grade only. b. Elevated Common Open Space. Elevated common open space, including rooftop decks and upper-level exterior courtyards located above the first habitable floor, shall not be oriented toward an adjacent lot with an R-1 zoning designation and shall be located a minimum of eighty (80) feet from any shared lot line with an R-1 zoned lot. The sum of all elevated common open space areas on a single building shall not exceed fifty (50) percent of the building footprint.
c. 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 (15) feet in width, or a screening element (such as a wall, trellis, or similar) with a minimum height of six (6) feet above the finished grade. A Atherton Municipal Code – SB 79 Ordinance (Administrative Draft) – February 2026
minimum of fifty (50) percent of the common open space perimeter facing an R-1 lot shall include evergreen planting.
d. 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 (40) percent of the open space requirement for a project.
b. Minimum Dimensions. Private open spaces shall have a minimum area of forty (40) square feet and a minimum dimension of five (5) feet in each direction. c. All private open space shall be outdoors.
d. Balconies or 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 (25) 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.
Atherton Municipal Code – SB 79 Ordinance (Administrative Draft) – February 2026
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. Plantings shall reach a minimum height of twelve (12) feet within three (3) years of planting.
c. All trees and shrubs shall be evergreen.
d. If the lot line is screened with existing landscaping that is at least twelve (12) 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 (4) 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.
Atherton Municipal Code – SB 79 Ordinance (Administrative Draft) – February 2026
Figure 17.59.030-3. Vertical Façade Organization
2. Horizontal Façade Organization.
Any building side greater than eighty (80) 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 (80) feet in length shall provide two (2) or more modules. Each module shall have a minimum width of forty (40) feet and a maximum width of one hundred (100) feet and shall include a minimum of one (1) bay and a maximum of nine (9) bays. Individual modules shall be differentiated by incorporating at least two (2) 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 section 17.59.030.I. v. A change in window pattern
vi. A change in eave or parapet height
vii. A recess or projection that is at least two (2) 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 (6) feet and a maximum width of forty (40) feet. Bays are not required to be equal in width.
A bay shall meet all of the following requirements:
Atherton Municipal Code – SB 79 Ordinance (Administrative Draft) – February 2026
i. At least twenty five (25) 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 (20) 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 and sixty (160) feet per building, as measured wall-to wall.
2. Massing Features. Massing features shall be provided along any building façade exceeding eighty (80) 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 (30) feet is maintained between features. Where two (2) 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.
Building Length Features Required Allowable Massing
Features
Up to 80 feet None • Tower
Atherton Municipal Code – SB 79 Ordinance (Administrative Draft) – February 2026
Greater than 80 feet, up to 120 feet 1
Greater than 120 feet, up to 160 feet 2
• Stepback
• Projection
• Recess
Massing features are allowed to encroach into a setback up to a maximum of five (5) 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 (10) feet, maximum of thirty (30) feet ii. Height. A tower may exceed the maximum building height for up to a maximum of ten (10) feet.
iii. Projection or Recess. Provide a minimum three (3) foot projection or recess from the immediately adjacent façade. This shall not be counted as the recess or projection feature in subsection (c).
iv. Bays. The tower includes at least one (1) and a maximum of three (3) 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.
Atherton Municipal Code – SB 79 Ordinance (Administrative Draft) – February 2026
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 (10) feet.
ii. Length and Location. A minimum length of twenty (20) 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 (3) foot.
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 setback from the building façade a minimum of one (1) foot.
iv. Bay Windows. May project into the front setback up to three (3) feet if located on stories above the ground floor. Each bay window is limited to a maximum width of 8 feet and must be separated from an adjacent bay window by 2 feet. The glass areas of each bay window must be at least 50 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. Primary entries. A primary entry shall be provided to access to 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 (1) of the frontage typologies listed in standards I.2 through I.4 below. Frontage typologies can be combined and can encroach into the front setback up to a maximum of five (5) feet.
Atherton Municipal Code – SB 79 Ordinance (Administrative Draft) – February 2026
2. 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
Common Entry
Minimum Maximum
Depth 2 feet 6 feet
Width 8 feet 16 feet
Height (Clear) 8 feet 14 feet
Weather protection shall be provided with a projection or recession with a minimum depth of four (4) feet.
A common entry shall provide access to all units located above the ground floor.
Figure 17.59.030-6. Common Entry Requirements
Atherton Municipal Code – SB 79 Ordinance (Administrative Draft) – February 2026
Atherton Municipal Code – SB 79 Ordinance (Administrative Draft) – February 2026
3. 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
Stoop
Minimum Maximum
Depth (Landing) 3 feet 8 feet
Width (Landing) 5 feet 8 feet
Width (Stairs) 4 feet 8 feet
Height (Landing) 1 foot 4 feet
Weather protection shall be provided with a projection or recession for a minimum depth of twelve (12) inches.
A stoop shall provide direct access to no more than two (2) units.
Figure 17.59.030-7. Stoop Requirements
Atherton Municipal Code – SB 79 Ordinance (Administrative Draft) – February 2026
4. 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).
Table 17.59.030.I.4. Frontage Court Requirements
Frontage Court
Minimum Maximum
Depth 15 feet 30 feet
Width 25 feet 50 feet
Height (above grade) No Minimum 1 foot
A frontage court shall provide direct access to no more than four (4) units.
The height of sidewalls facing the courtyard shall not exceed a 2:1 ratio to its depth or width.
Figure 17.59.030-8. Frontage Court Requirements
Atherton Municipal Code – SB 79 Ordinance (Administrative Draft) – February 2026
Atherton Municipal Code – SB 79 Ordinance (Administrative Draft) – February 2026
5. 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
Minimum Maximum
Depth 10 feet 24 feet
Height (above grade) 1 foot 3 feet
Height (wall or railing) 30 inches 42 inches
Terrace stairs shall be spaced no more than twenty-five (25) feet apart.
A terrace shall provide direct access to no more than four (4) units.
Figure 17.59.030-9. Terrace Requirements
Atherton Municipal Code – SB 79 Ordinance (Administrative Draft) – February 2026
Atherton Municipal Code – SB 79 Ordinance (Administrative Draft) – February 2026
6. Minimum window detail requirements are:
a. Windows shall be recessed at least two (2) 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 (2) 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 a minimum sill height of fifty-four (54) inches or translucent, but not transparent, glazing for any part of the window glass less than fifty-four (54) inches above the finished floor. See figure 17.59.030-11 (Window Privacy).
Atherton Municipal Code – SB 79 Ordinance (Administrative Draft) – February 2026
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 (3) colors and three (3) materials; window trim and fascia are excluded from this limit.
b. Heavier façade materials shall be placed beneath lighter materials.
Atherton Municipal Code – SB 79 Ordinance (Administrative Draft) – February 2026
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 Section G.1, 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 (4) feet on the main building.
2. Roof parapets, when included, shall be a minimum of three (3) feet tall and may not exceed the maximum building height.
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 (8) 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 Atherton Municipal Code – SB 79 Ordinance (Administrative Draft) – February 2026
shielded to restrain light to a minimum thirty (30) 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 (5) 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 a setback that faces a public right-of-way. Accessory buildings shall be set back from the lot line for a minimum of five (5) feet, or a minimum of fifteen (15) feet on a shared lot line with a lot with an R-1 zoning designation.
2. Trash and Recycling Enclosures.
a. Trash disposal and recycling areas shall be within an enclosure and shown on the site plan.
b. Each enclosure shall screen trash and recycling receptacles from public view. c. Trash and recycling enclosures shall be a minimum of six (6) feet and a maximum of eight (8) 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.
3. Mailboxes.
a. Mailboxes shall be clustered in a common centralized interior location that is part of or within twenty-five (25) 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.
Atherton Municipal Code – SB 79 Ordinance (Administrative Draft) – February 2026
b. Total resident and guest parking shall not exceed one-and-a-quarter (1.25) spaces per unit.
c. Total resident and guest parking can be increased to a maximum of two (2) 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 (5) feet from a side or rear lot line.
2. Parking Garage Design.
a. No more than twenty-five (25) 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 (20) 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 (5) feet above grade and shall provide landscape screening with a minimum depth of ten (10) 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 (1) bicycle parking space per every two (2)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 (25) feet of a public rightof-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.
Atherton Municipal Code – SB 79 Ordinance (Administrative Draft) – February 2026
Atherton Municipal Code – SB 79 Ordinance (Administrative Draft) – February 2026
Atherton Municipal Code – SB 79 Ordinance (Administrative Draft) – February 2026
Chapter 17.60
DEFINITIONS
“Lot area, net” means the portion of gross site area remaining after deducting from the following:
1. Any portion of a lot within the right-of-way of an existing public or private street, road or access easement, except an emergency access street.
2. The portion of a flag lot constituting the access corridor lying between the front lot line and the frontage line at the street.
“Net habitable square footage” means the finished and heated floor area fully enclosed by the inside surface of walls, windows, doors, and partitions, and having a headroom of at least six and one-half feet, including working, living, eating, cooking, sleeping, stair, hall, service, and storage areas, but excluding garages, carports, parking spaces, cellars, half-stories, and unfinished attics and basements.
“Open space” means an area designed and accessible for outdoor living, recreation, and/or pedestrian access. Areas for parking, loading, or storage shall not be counted as open space. “Open space, common” means an outdoor area that is designed for the common use of residents within a development, is accessible to multiple dwelling units, and is not reserved for the exclusive use of any individual unit. Common open space includes courtyards, plazas, rooftop decks, and similar communal spaces, but does not include private balconies, patios, or rooftop decks assigned to individual units.
“Open space, private” means an outdoor area that is directly accessible from and reserved for the exclusive use of a single dwelling unit, such as a balcony, patio, or deck. Private open space does not include shared courtyards, common areas, required setbacks, or landscaped buffers.