In short
- 718 ADU permits on record, nearly all since 2018.
- 132 in 2025, down 22% from 2024.
- Typical permit time: 335 days from application to permit (median of 260 permits with both dates recorded).
About this data
- Source: California HCD Housing Element Annual Progress Reports. The state data does not say whether an ADU is detached, attached, a garage conversion or a JADU, so most records show as 'unknown'. Permit valuations are not published in this source. Timelines use the application date the city reported to the state, matched to the permit where possible; some cities report their planning application date, so timelines can include planning review. Each project is counted once, in its building-permit year (or completion year when no permit date was reported).
Permits by year
Permits by year and type (table)
| Year | All ADU permits | Garage conversions | Detached |
|---|---|---|---|
| 1999 (partial records) | 1 | — | — |
| 2018 | 21 | — | — |
| 2019 | 60 | — | — |
| 2020 | 46 | — | — |
| 2021 | 77 | — | — |
| 2022 | 106 | — | — |
| 2023 | 105 | — | — |
| 2024 | 170 | — | — |
| 2025 | 132 | — | — |
“—” means the source for that year does not report ADU type.
Read more: ADU types explained
Not counted above: 4 approved projects with no building permit reported yet.
ADU rules in Santa Monica
State law check: HCD found the 2023 ordinance noncompliant (February 26, 2024), including its one-ADU limit and rear-of-lot rule; the city amended it in October 2024 and May 2025. We haven't seen HCD's response.
| Rule | Santa Monica's code | State law guarantees |
|---|---|---|
| Maximum size | 850 sq ft (studio or 1 bedroom) or 1,200 sq ft (2+ bedrooms); a conversion or addition to the house is capped at 50% of it. State-law detached ADU 800 sq ft. Junior ADU 500 sq ft. | At least 850 sq ft (1,000 sq ft with 2+ bedrooms) must be allowed; an 800 sq ft detached ADU always is. Conversions of existing space have no size cap. Junior ADU: up to 500 sq ft. |
| Height | Detached: 2 stories or 24 ft. Inside or attached to the house: the zone's limit. | Detached: at least 16 ft (18 ft within ½ mile of transit, plus 2 ft for a matching roof). Attached: 25 ft or the zone's limit, whichever is lower. |
| Setbacks | 4 ft side and rear; the zone's front setback; none for conversions. | No more than 4 ft side and rear; none for conversions of existing space. |
| Parking | None required; no replacement parking. | At most 1 space; none within ½ mile of transit and in several other cases. No replacement parking when a garage is converted. |
| Owner living on site | None for ADUs. Junior ADU: required, with a deed restriction. | None for ADUs. A junior ADU that shares a bathroom with the house requires the owner to live in one of them. |
| How many on a single-family lot | One converted ADU, one junior ADU and one detached ADU, plus one more ADU in the R1 zone. | One ADU converted from existing space, one junior ADU and one new detached ADU (up to 800 sq ft). From January 1, 2027: two new detached ADUs (a city then needn't allow a junior ADU on that lot). |
| Short-term rentals | Not for 30 days or less, except as the city's home-sharing rules allow. | No guarantee: cities may require rentals of more than 30 days, and junior ADUs can't be short-term rentals. |
- Coastal Zone: a Coastal Development Permit or waiver from the California Coastal Commission may also be needed.
- The extra R1 ADU must be a deed-restricted rental or sold as a condominium; ADUs can be sold separately as condominiums.
- ADUs are exempt from the city's affordable housing, child care, transportation and parks fees.
Where local rules conflict with state law, state law controls. Sources: Santa Monica Municipal Code § 9.31.025 (Ord. 2814CCS, May 27, 2025) · Santa Monica ADU and JADU Guide, single-unit parcels (Nov 2025) · HCD findings (Feb 26, 2024); HCD's list of review letters; California ADU rules. Verified Sep 30, 2026. Rules change and every lot is different: confirm with the city before you design.
How long permits take
| Type | Median days, application to permit | Middle half | Permits |
|---|---|---|---|
| Unclassified | 335 | 219 – 490 | 260 |
Middle half: the range covering the middle 50% of permits (a quarter were lower, a quarter higher).
Read more: How long ADU permits take in Los Angeles (and other cities) · How long ADUs take to build
From permit to completion
Of the 328 ADU permits Santa Monica reported issuing from 2020 through 2023, 53 (16%) have a completion reported to the state. For those, the median time from permit to completion was 13 months.
The state reports don't record expired or cancelled permits, and a completion the city hasn't reported looks the same as an unfinished project, so the share is a floor. Years with incomplete reports are left out.
What neighbors declared as cost
Cost data (declared permit valuations) is not published for this area in these sources.
Read more: How to choose an ADU builder
An ADU builder serving Santa Monica? Feature your business on this page.
Questions about ADUs in Santa Monica
How many ADUs have been permitted in Santa Monica?
Public records show 718 ADU permits in Santa Monica through 2025, nearly all since 2018. 132 in 2025, down 22% from 2024. These counts come from the city's reports to the state, which place a project in its completion year when no permit date was reported.
How long does an ADU permit take in Santa Monica?
Among the 260 ADU permits in Santa Monica with both dates recorded, half were issued within 335 days of the application; the middle half took 219 to 490 days. That includes plan-check corrections and resubmittals, not just the review itself.
Can I build an ADU on my property in Santa Monica?
California law allows ADUs on most lots with a house, including in Santa Monica, but what you can build depends on your lot, local rules and utilities. This site shows permits, not eligibility. See California ADU rules.
Where do I apply for an ADU permit in Santa Monica?
Apply with the City of Santa Monica's Community Development Department for a building permit only (no design review); the city runs a pre-approved ADU plan program. Official ADU page.
How current is this?
- State annual progress reports: through 2025 (published once a year)
How our data works · Download the data · Free to reuse with credit to SoCal ADU Tracker (socaladutracker.com), under CC BY 4.0.