ADU Rules in Santa Monica, CA (2026)
ADU rules, permit requirements, size limits, and fees for Santa Monica, CA. Source-cited from official municipal code.
Yes, ADUs are allowed in Santa Monica, CA.
Santa Monica, CA permits accessory dwelling units (ADUs) on residential properties. ADUs — also called granny flats, in-law units, backyard cottages, or secondary suites — are secondary housing units on a single-family or multifamily lot. California state law actively preempts local restrictions, making ADU approval a streamlined ministerial process. In Santa Monica, the Santa Monica Community Development Department — Building and Safety Division handles ADU permit applications. Below you will find the current size limits, setbacks, fees, and timeline for building an ADU in Santa Monica.
ADU Size Limits
ADU Size Limits in Santa Monica: Detached ADU: size varies by zoning — see official source (max height: varies — see official source). Attached ADU: 50 percent of the existing primary dwelling. Junior ADU (JADU): up to 500 sq ft — must be within the existing primary dwelling or accessory structure.
| Type | Max Size | Max Height |
|---|---|---|
| Detached ADU | See official source | See official source |
| Attached ADU | 50 percent of the existing primary dwelling · Verified June 4, 2026 · Source | See official source |
| JADU | 500 sq ft · Verified June 4, 2026 · Source | Within existing structure |
Permit Fees
ADU Permit Fees in Santa Monica: Plan check fee: Varies. Building permit fee: Varies. Impact fees: None. School fees: None or N/A. Total estimated permit cost: Varies.
| Fee Type | Amount |
|---|---|
| Plan Check | See official source |
| Building Permit | See official source |
| Impact Fees | None |
| School Fees | See official source |
| Total Estimate | See official source |
Permit Timeline
Santa Monica ADU Permit Timeline: The permitting agency shall either approve or deny the application to create or serve an accessory dwelling unit within 60 days from the date the permitting agency receives a completed application if there is an existing single-family or multifamily dwelling on the lot. Apply through the Santa Monica Community Development Department — Building and Safety Division online permit portal. Phone: (310) 458-8355.
Setback Requirements
ADU Setback Requirements in Santa Monica: Front setback: follows zone standard. Side setback: 4 feet. Rear setback: 4 feet.
Parking Requirements
Parking Requirements: No additional parking required for ADUs within one-half mile of Metro Expo Line (E Line) stations (17th St/SMC, Downtown Santa Monica) or Big Blue Bus routes. No replacement parking when garage converted to ADU. Per California Gov Code §66322(a)(1) and §66314(d)(11) (Stats. 2024 Ch. 7 §20).
Restrictions & Requirements
How Many ADUs Are Allowed?
Number of ADUs Allowed in Santa Monica: Single-family lots: 1 ADU + 1 JADU per single-family lot. Multifamily properties: Up to 25% of existing units (minimum 2) as detached ADUs; internal conversions permitted per state law. CRITICAL NOTE: Santa Monica Rent Control (RCCA) may apply to newly created ADUs in certain circumstances. Consult a Santa Monica rent control attorney before creating an ADU if you have existing tenants or multifamily buildings. New ADUs in newly built structures (post-1995) are generally exempt from rent control under Costa-Hawkins.
- Single-Family Lots
- See official source
- Multifamily Properties
- See official source
Statewide Preemption
ADU Preemption
California state law preempts local ADU rules — local governments cannot impose stricter standards.
View California preemption detailsState Law & Preemption
State Preemption: California Government Code Chapter 13 (§§66314–66333, effective January 1, 2025 per Stats. 2024 Ch. 7, SB 477) preempts Santa Monica's local ADU restrictions. Santa Monica must permit ADUs by-right on all residential lots, despite local rent control and strict housing regulations. Owner-occupancy requirement eliminated per §66315 (AB 68, 2019; Stats. 2024 Ch. 7 §20). Santa Monica's SMMC Chapter 9.31.290 implements state ADU law.
Historic District Considerations
Historic District Requirements: Santa Monica has 4 historic districts where additional design review may be required for ADU construction. Design review approval is required before obtaining a building permit for properties in historic overlay zones. Santa Monica has 4 locally-designated landmark districts: Wilshire Montana Boulevard Neighborhood Historic District, Fourth Street Historic District, and portions of the Ocean Park neighborhood. The Santa Monica Landmarks Commission oversees preservation. Individually-landmarked properties (over 100 in the city) require Certificate of Appropriateness for exterior alterations. The city has a Miramar Hotel historic designation important for that redevelopment project. Look up historic district boundaries at: https://www.santamonica.gov/departments/community-development/planning/landmarks-commission
Frequently Asked Questions
Can I build an ADU in Santa Monica?
Yes. Santa Monica, CA allows accessory dwelling units. On a single-family lot you can build 1 ADU + 1 JADU per single-family lot.
How big can an ADU be in Santa Monica?
The maximum size for a detached ADU in Santa Monica is 1,200 square feet. A Junior ADU (JADU) can be up to 500 square feet.
How long does it take to get an ADU permit in Santa Monica?
The typical ADU permit timeline in Santa Monica is The permitting agency shall either approve or deny the application to create or serve an accessory dwelling unit within 60 days from the date the permitting agency receives a completed application if there is an existing single-family or multifamily dwelling on the lot.. Total estimated permit fees are $3,000–$12,000 total permit fees — higher than most CA cities due to Santa Monica's premium fee schedule.
Do I need extra parking for an ADU in Santa Monica?
Santa Monica parking rules for ADUs: No additional parking required for ADUs within one-half mile of Metro Expo Line (E Line) stations (17th St/SMC, Downtown Santa Monica) or Big Blue Bus routes. No replacement parking when garage converted to ADU. Per California Gov Code §66322(a)(1) and §66314(d)(11) (Stats. 2024 Ch. 7 §20).
Do I have to live on-site to have an ADU in Santa Monica?
Owner-occupancy requirement in Santa Monica: No additional standards, other than those provided in Section 66314, shall be used or imposed, including an owner-occupant requirement.
Source: Santa Monica Municipal Code Chapter 9.31.290 — Accessory Dwelling Units; California Government Code §§66314–66333 (Stats. 2024 Ch. 7 §20). Last verified April 6, 2026. View source