Accessory Dwelling Unit (ADU) Ordinance Update
Aastha Vashist, Senior Planner
City Council, March 25, 2025
2City of Sunnyvale – ADU ordinance update– March 2025
• ADUs & JADUs provide an affordable and effective solution towards increasing housing • Sunnyvale Municipal Code (SMC) Chapter 19.79 (ADU Ordinance) Last amended in January 2023 (Ord. No. 3209-23)
Several state ADU-related laws passed since then
Proposed ADU Ordinance Update:
•Repealing the current ADU Ordinance and adopting an updated ADU Ordinance •Goal: Consistency with state laws and improving readability and clarity of ADU regulations
Background
3City of Sunnyvale – ADU ordinance update– March 2025
Recent State Legislation
Summary Staff Comments
AB 1332 Develop a program for the preapproval of
new construction ADUs
Pre-approved ADU section is now
on the City’s website
AB 976 Prohibits owner occupancy requirement for
“standard” ADUs (still required for JADUs)
Included in update
AB 1033 Allows cities to permit the separate sale or
conveyance of primary dwelling units and
ADUs as condominiums.
Not recommended and not
included in update
SB 477 State ADU Law Reorganization No update required
SB 1211 Increase in allowable # of Multifamily ADUs Included in update AB 2533 Prohibits local agencies from denying permits
for unpermitted ADUs and JADUs built before
January 1, 2020.
Working on updating the City’s
website to ensure public
awareness
4City of Sunnyvale – ADU ordinance update– March 2025
Key Municipal Code Updates
Chapter 19.12 (Definitions)
Other Zoning Code Chapters
Number of Allowed ADUs
Streamlining Provisions
JADU Deed Restriction
Other Enhancements
5City of Sunnyvale – ADU ordinance update– March 2025
Definitions (SMC Chapter 19.12)
Clarifications to ADU
types
• New Construction
• Conversion
• Attached and
Detached
Modifying Existing
Definitions
• JADUs
• Gross Floor Area
• Accessory
structure
• Building, main
• Lot Coverage
New Definitions
• Habitable area
• Multifamily
dwelling structure
• Nonconforming
zoning condition
• Objective standards
• Proposed dwelling
• Public Transit
6City of Sunnyvale – ADU ordinance update– March 2025
Updates to Other Zoning Code Chapters
• SMC Table 19.37.040 updated to remove usable
open space requirement for ADUs
Ch. 19.37
Landscaping, Irrigation
and Usable Open Space
• SMC Section 19.82.020 (a)(1) updated to
reference the proposed ADU Ordinance section
Ch. 19.82
Miscellaneous Plan
Permit
• SMC Section 19.50.020 updated to reference
proposed ADU Ordinance section
Ch. 19.50
Nonconforming Buildings
and Uses
7City of Sunnyvale – ADU ordinance update– March 2025
Number of Allowed ADUs
Existing Code Proposed Code
Single-family
dwelling lots
• Total 2
• One ADU
• One JADU
• Total 3
• One conversion ADU
• One detached or attached new
construction ADU
• One JADU
Multi-family
dwelling lots
• Max. 2 detached, new
construction ADUs
• Max. 25% of existing # of
units converted
• Max. 8 detached, new construction
ADUs (
not more than # of existing units)
• No change to # of conversion ADUs
8City of Sunnyvale – ADU ordinance update– March 2025
Streamlining Provisions
Existing Proposed
Streamlined
ADUs
(no planning
permit)
• Detached, new construction
ADUs up to 800 s.f.
• Conversion ADUs
• JADUs
• Attached or detached, new
construction ADUs up to 800 s.f.
• Detached New Construction ADUs
(for multi-family dwelling lots)
• Conversion ADUs
• JADUs
• ADUs completely within basement
Non-
streamlined
ADUs
(requires MPP)
• Attached, new construction
ADUs
• Detached, new construction
ADUs over 800 s.f.area.
• Attached or detached, new
construction ADUs over 800 s.f. area
(for single-family dwelling lots)
9City of Sunnyvale – ADU ordinance update– March 2025
JADU Deed Restriction
Retain ownership occupancy requirement
• Prohibition on a separate sale from the single-family residence.
Also applies to future purchasers.
• Adherence to the max. 500 s.f.area and compliance with all requirements.
Expanded deed restriction requirement, including:
10City of Sunnyvale – ADU ordinance update– March 2025
Other Enhancements
Reorganization
(by single-family and multi-
family dwelling requirements)
Clarification of development
standards
(e.g. second floor balconies and
windows, solar analysis, front
setbacks, mechanical
equipment etc.)
Consistency with current state
legislation
11City of Sunnyvale – ADU ordinance update– March 2025
FEBRUARY 10, 2025
Planning Commission Hearing
• Voted 7-0 to Recommend Alternative 1 (as recommended by staff) • Discussion:
Accessibility requirement
Tree replacement
Heritage resource requirements
12City of Sunnyvale – ADU ordinance update– March 2025
Tree replacement requirement
• Removal of protected trees Chapter 19.94
• One 15-gallon replacement tree for every
protected tree removed.
• Recommendation: apply the tree
replacement requirement only to non-
streamlined ADU.
Removal of Heritage Trees & Resources
for an ADU
• Sunnyvale's Heritage Resource Inventory
includes ~20 heritage trees
• Recommendation: remove Section
pertaining to Heritage Trees and Heritage
Resources
Ordinance Updates
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Recommendation
Recommend:
1. Introduce an Ordinance Amending Title 19 (Zoning) of the Sunnyvale Municipal Code on Accessory Dwelling Units and find the action is exempt from CEQA.
2. Alternative 1 with modifications to the ordinance.
3. Do not introduce the ordinance and provide feedback on desired changes.
Alternatives
Staff Recommendation
Recommend Alternative 1.