Town of Atherton
ADU Ordinance Update
City Council
November 15, 2023
1 Recommendation
Staff recommends that City Council conduct a public
hearing to introduce an ordinance to:
• repeal and replace Chapter 17.52 “Accessory Dwelling
Units,” and
• amend Chapter 17.36 “Public Facilities and Schools
District (PFS)” and Chapter 17.60 “Definitions.”
2 Background
Major
overhaul
of ADU
legislation
by State
2019
Town
updates
ADU
Ordinance
2020
Ongoing
changes to
State law
2020 -
2023
Town
updates to
align with
State law
Now
3 6
th Cycle
Housing Element
Process
2022 -
Now
Areas of Change
4 • Definitions
• Accessory Dwelling Use
• Maximum Number of
Units
• Floor Area Requirements
• Exemptions from
Maximum Floor Area
Requirements
• Basements
• Setback Requirements
• Height
• Heritage Trees
• Privacy, Screening and
Landscaping
• Parking Requirements
• Owner Occupancy
• Passageways and Internal
Connections
• Compliance with Applicable
Requirements
• Impact Fees
• Utilities
• Certificate of Occupancies
• Code Enforcement
• Public Facilities and School
Districts (PFS) Zoning
Controls
• “Kitchen” and “Efficiency
Kitchen” Definitions
Areas of Change – Per State Law
5 • Definitions
• Accessory Dwelling Use
• Maximum Number of
Units
• Floor Area Requirements
• Exemptions from
Maximum Floor Area
Requirements
• Basements
• Setback Requirements
• Height
• Heritage Trees
• Privacy, Screening and
Landscaping
• Parking Requirements
• Owner Occupancy
• Passageways and Internal
Connections
• Compliance with Applicable
Requirements
• Impact Fees
• Utilities
• Certificate of Occupancies
• Code Enforcement
• Public Facilities and School
Districts (PFS) Zoning
Controls
• “Kitchen” and “Efficiency
Kitchen” Definitions
(Changes required by State law)
Inserting Town Influence
6 Bonus ADU
Program
Number of ADUs
Deed Restricted
Affordability
ADUs above
Garages
Height, Setbacks,
Floor Area
Roofline, Entry
Locations,
Window
Treatments
Heritage
Trees
Flexibility for
+800sf ADUs
Review Process
Town Objectives:
1) Incentivize compliance with Town’s standards
2) Incentivize ADU development to meet the Town’s RHNA objectives Maximum Number of Units
7 (e) (1) Notwithstanding subdivisions (a) to (d), inclusive, a local agency shall ministerially approve an application for a building permit within a residential or mixed-use zone to create any of the following:
(A) One accessory dwelling unit or one junior accessory dwelling unit per lot with a proposed or existing single-family dwelling if all of the following apply… (B) One detached, new construction, accessory dwelling unit that does not exceed four-foot side and rear yard setbacks for a lot with a proposed or existing single-family dwelling. The accessory dwelling unit may be combined with a junior accessory dwelling unit described in subparagraph (A)… State Law (how it used to be):
1 ADU or 1 JADU (subject to conditions)
1 detached, new construction, ADU
2 units
+
=
Maximum Number of Units
8 (e) (1) Notwithstanding subdivisions (a) to (d), inclusive, a local agency shall ministerially approve an application for a building permit within a residential or mixed-use zone to create any of the following:
(A) One accessory dwelling unit and one junior accessory dwelling unit per lot with a proposed or existing single-family dwelling if all of the following apply… (B) One detached, new construction, accessory dwelling unit that does not exceed four-foot side and rear yard setbacks for a lot with a proposed or existing single-family dwelling. The accessory dwelling unit may be combined with a junior accessory dwelling unit described in subparagraph (A)… State Law (now):
1 ADU (subject to conditions)
1 JADU (subject to conditions)
1 detached, new construction, ADU
3 units
+
=
Bonus ADU Program
9 Allow the zoning code to allow two ADUs to be constructed on properties two acres or greater than area.
Housing Element Program 3.812(F):
1 ADU (subject to conditions)
1 JADU (subject to conditions)
1 detached, new construction, ADU
3 units
+
=
+
1 BONUS ADU
(+2 ACRE LOTS
ONLY)
• Timeframe:15 years
• Affordability level: “Low-Income”
Deed Restriction Component:
ADUs Above Garages
10 Height
• Maximum
height of
structure
(including
garage and
ADU)
• Roof form
Floor Area
Exemptions
• Ground level
entry
• Enclosed stairs
Privacy
• No
balconies/decks
• Window
standards
• 8 foot fencing
• Landscaping
Objective:
Incentivize compliance with Town’s setbacks by
allowing ADUs above existing or proposed detached garages Heritage Trees
11 TPZ Exceptions
• Administrative up
to 6x in the R1-A
Review Process
• Reviewed during
Planning
consideration
• 6x would require
information at
submittal of
application
Good Faith
Removal
• Asserts timeline
requirements for
ADU construction
• Asserts potential
penalties
Objective:
Incentivize compliance with Town’s setbacks by providing greater flexibility with Heritage Tree Ordinance for larger, setback compliant ADUs Next Steps
12 City
Council
• Consideration of Draft Ordinance
• Adopted Ordinance sent to State
for review
HCD
• Review of Ordinance, required
changes back to Planning Commission
and City Council for consideration.
Housing
Element
• HCD Certification of Ordinance
supports Town’s progress with
Housing Element programs
Recommendation
Staff recommends that City Council conduct a public
hearing to introduce an ordinance to:
• repeal and replace Chapter 17.52 “Accessory Dwelling
Units,” and
• amend Chapter 17.36 “Public Facilities and Schools
District (PFS)” and Chapter 17.60 “Definitions.”
13 Thank you
14