Santa Monica allows ADUs and JADUs on any residential parcel under SMMC 9.31.025, with detached units up to 1,200 sq ft and 24 ft tall, no parking requirements, and a local ADU condominium ordinance (SMMC 9.31.026) permitting separate sale. The big local wrinkle is the Coastal Zone — properties west of Lincoln Blvd/4th St need a Coastal Development Permit through the California Coastal Commission.
Zoning & Size Requirements [1][2][3]
| Allowed Zones | Any legal parcel zoned for single-unit or multiple-unit residential use (including residential and mixed-use properties) with an existing or proposed dwelling (SMMC 9.31.025) |
| Max Size (Detached) | 850 sq ft (studio/1-bedroom) or 1,200 sq ft (2+ bedrooms) |
| Max Size (Attached) | 850 sq ft (studio/1-BR) or 1,200 sq ft (2+ BR), but not more than 50% of the existing primary dwelling (minimum 800 sq ft guaranteed for conversions of the primary dwelling) |
| Max Size (JADU) | 500 sq ft (within the footprint of an existing or proposed single-unit dwelling) |
| Max Height | Detached: 2 stories or 24 ft (measured per SMMC 9.04.050, typically from Average Natural Grade); attached ADUs and JADUs: underlying zoning district height limits for the primary dwelling |
| Max Units | Single-unit-dwelling parcels may combine: 1 converted ADU + 1 JADU + 1 detached ADU, plus 1 additional attached ADU on R1-zoned parcels — up to 3 accessory units alongside the main home |
Setback Requirements [1][2][3]
| Rear Setback | 4 ft; none for conversions of existing structures (including pre-Jan 1, 2020 unpermitted structures being legalized) |
| Side Setback | 4 ft; minimum 4 ft separation between a detached ADU and the primary dwelling, measured between exterior walls |
| Front Setback | Not permitted within the required front setback of the underlying zone (JADUs within existing structures are exempt) |
| Parking Required | No on-site parking required; parking eliminated by a garage conversion does not need to be replaced (contact Rent Control re: rent-controlled parking amenities; Coastal Zone parcels should confirm with the Coastal Commission) |
| Owner Occupancy | Not required for ADUs. City guide requires owner-occupancy for JADUs (SUD or JADU); AB 1154 (eff. Jan 1, 2026) removes this for JADUs with separate sanitation — state law prevails |
| Min Lot Size | No minimum |
Permit Process & Fees [4][5]
| Approval Process | Ministerial — building permit only, no design review or hearings, via the city's all-online Electronic Plan Review (Citizen Access + ProjectDox). Coastal Zone parcels additionally need a Coastal Development Permit or waiver through the California Coastal Commission before building permit submittal |
| Review Timeline | 60 days — application deemed approved if the city does not act within 60 days (SMMC per SB 543, eff. Jan 1, 2026); Coastal Zone CDP adds months to the front end |
| Permit Fees | Valuation-based plan check and building permit fees paid through Citizen Access; confirm current totals with Santa Monica Building & Safety via the 311 system |
| Impact Fees | ADUs under 750 sq ft are exempt from residential impact fees; 750 sq ft and larger pay fees proportional to the primary dwelling size (includes Santa Monica-Malibu USD school fees) |
| Plan Check | Electronic Plan Review with corrections issued through ProjectDox; fee set by fee schedule at submittal |
| Pre-Approved Plans | Program established (under AB 1332) for vendor-submitted preapproved Standard ADU Plans — detached ADUs only, no modifications allowed; as of mid-2026 no vendor plans are listed yet ('NONE AT THIS TIME') |
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Construction Costs [6][7]
| Average Build Cost | $250,000-$500,000 |
| Cost per Sq Ft | $350-$550 |
| Garage Conversion | $140,000-$245,000 |
| Prefab ADU (Installed) | $200,000-$350,000 |
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Rental Income Potential [8][9]
| Avg Rent (1 Bedroom) | $3,000-$3,700/mo |
| Avg Rent (2 Bedroom) | $4,000-$4,700/mo |
| Short-Term Rental | No — ADUs/JADUs may not be rented for terms of 30 days or less |
| Est. Annual ROI | 5-8% annual return |
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Recent Law Changes
What's Changed Recently
- SMMC 9.31.026 (Accessory Dwelling Unit Condominiums): Santa Monica has opted into AB 1033 — ADUs on single-unit-dwelling parcels may be sold separately as condominiums (JADUs excluded)
- Santa Monica Municipal Code current through Ordinance No. 2857CCS (adopted April 28, 2026)
- City ADU/JADU Guides for single-unit-dwelling parcels republished November 2025 with updated size, height and setback tables
- SB 543 (eff. Jan 1, 2026): ADU applications deemed approved if the city fails to act within 60 days — codified in SMMC 9.31.025
- AB 1154 (eff. Jan 1, 2026): JADU owner-occupancy requirement removed statewide for JADUs with separate sanitation facilities
- HCD review letter (Feb 26, 2024): HCD reviewed Santa Monica's ADU ordinance for state-law compliance; subsequent code updates followed
Tips for Building an ADU in Santa Monica
- Check gisdata.santamonica.gov before anything else: the Coastal Zone (beach to 4th St north of Pico, beach to Lincoln Blvd south of Pico, plus Ocean Park) requires a Coastal Development Permit from the Coastal Commission before you can even submit for a building permit
- R1 parcels get a bonus: besides a converted ADU, a JADU and a detached ADU, you can add one attached ADU — one of the few LA-area cities where a single-family lot can legally hold four units this way
- Santa Monica is an AB 1033 city — a detached ADU can be deed-restricted as a rental or sold separately as a condo under SMMC 9.31.026, which changes the financing options
- Unpermitted structures built before Jan 1, 2020 can often be legalized as ADUs with no setback compliance required — get written permit-history verification from Building & Safety first
- If your garage conversion removes parking that was an amenity for a rent-controlled unit, contact the Rent Control Department first — rent adjustments may apply
Sources & References
All data on this page is sourced from official government records and verified market data. View our full methodology.
- ADU and JADU Guide — Parcels with a Single-Unit Dwelling (City of Santa Monica, Nov 2025) Planning Department — Accessed 2026-06-10
- Accessory Dwelling Units — santamonica.gov topic explainer Planning Department — Accessed 2026-06-10
- SMMC 9.31.025 Accessory Dwelling Units and Junior Accessory Dwelling Units Municipal Code — Accessed 2026-06-10
- Preapproved ADU Program — City of Santa Monica Planning Department — Accessed 2026-06-10
- Santa Monica ADU Handbook (City of Santa Monica, Sept 2022) Planning Department — Accessed 2026-06-10
- Santa Monica ADU Handbook cost estimates (City of Santa Monica) Planning Department — Accessed 2026-06-10
- ADU Cost Los Angeles 2026 — CALI ADU Market Data — Accessed 2026-06-10
- Average Rent in Santa Monica, CA — RentCafe (March 2026) Market Data — Accessed 2026-06-10
- Average Rent in Santa Monica, CA — Zumper Rent Research Market Data — Accessed 2026-06-10
Frequently Asked Questions
Can I build an ADU in Santa Monica?
Yes. ADUs are allowed in Any legal parcel zoned for single-unit or multiple-unit residential use (including residential and mixed-use properties) with an existing or proposed dwelling (SMMC 9.31.025) in Santa Monica. The maximum size for a detached ADU is 850 sq ft (studio/1-bedroom) or 1,200 sq ft (2+ bedrooms). No owner-occupancy is required.
How much does an ADU cost in Santa Monica?
ADU construction in Santa Monica typically costs $250,000-$500,000. Garage conversions run $140,000-$245,000, and prefab ADUs cost $200,000-$350,000.
How much can I rent an ADU for in Santa Monica?
Average ADU rents in Santa Monica are $3,000-$3,700/mo for a 1-bedroom and $4,000-$4,700/mo for a 2-bedroom unit.
Do I need parking for an ADU in Santa Monica?
No on-site parking required; parking eliminated by a garage conversion does not need to be replaced (contact Rent Control re: rent-controlled parking amenities; Coastal Zone parcels should confirm with the Coastal Commission). Check with Santa Monica planning department for the latest California ADU parking rules, as many states have relaxed requirements in recent years.
How long does it take to get an ADU permit in Santa Monica?
The permit review timeline in Santa Monica is 60 days — application deemed approved if the city does not act within 60 days (SMMC per SB 543, eff. Jan 1, 2026); Coastal Zone CDP adds months to the front end. Fees range from Valuation-based plan check and building permit fees paid through Citizen Access; confirm current totals with Santa Monica Building & Safety via the 311 system.
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