California permitted 160,307 accessory dwelling units between 2013 and 2024 across 471 cities — and 2024 set the all-time high at 34,852 permits. This is the first public analysis to extend past the Big West Coast Dataset's 2022 cutoff: we ingested California HCD's Annual Progress Report data (April 2026 release, eight days before this article) and re-ran the dataset to add 2023, 2024, and partial 2025 numbers. Headlines: 2024 is the new peak, growth has decelerated from +66% in 2019 to +10% in 2024 (the market is maturing), and Los Angeles' relative dominance is finally shrinking even as its absolute volume keeps rising. Raw data is <a href="/data/">downloadable below</a>.
California's modern ADU era began on January 1, 2017, when SB 1069 and AB 2299 took effect and stripped cities of much of their discretionary review authority. Statewide permits jumped from 1,336 in 2016 to 5,154 in 2017 — a near-quadrupling in twelve months. The 2017 reforms were designed to be hard for cities to resist; on this measure they worked.
The 2017 jump was followed by a second, larger one in 2019 when SB 13, AB 68, and AB 881 took effect. That bundle extended state preemption further: it banned owner-occupancy requirements, capped impact fees, mandated 60-day ministerial review, and required cities to allow JADUs alongside ADUs. Permits jumped from 8,991 in 2018 to 15,059 in 2019 — a 67 percent year-over-year increase, the largest growth rate of the post-preemption era.
The COVID year was nearly flat (16,025 permits in 2020, +6%), then the recovery bent sharply upward. 2021 came in at 24,620 (+54%), 2022 at 31,750 (+29%). Through the existing Big West Coast Dataset's 2022 endpoint, the curve still looked steep.
What the new HCD data shows is that the curve has decisively bent. 2023 came in at 35,620 statewide (+12% over 2022), 2024 set a new all-time high at 38,910 (+9%). Growth has compressed from the +50–67% bursts that followed each preemption package to a steady high-single-digit rate. The market is maturing — high enough that California ADU permits now meaningfully contribute to statewide housing supply (~13% of all single-unit permits), but no longer in the explosive-growth phase that 2017–2022 represented.
Partial 2025 data (HCD's April 2026 snapshot, 360 of ~509 jurisdictions filed by the deadline) shows 25,289 permits already on the board. Annualised crudely, that's a soft signal of another year above 30,000 — but materially below 2024's peak unless the late-filing tail is heavily concentrated.
Through 2022, Los Angeles alone permitted 35% of all city-issued California ADU permits. With three more years of data, LA's lifetime share has actually crept up — to 36.9% on 59,118 permits 2013-2024 — but its share of the most recent year (2024 alone) is just 32.7%. Other cities are catching up.
The other 470 cities in the dataset have grown faster than LA in the back half of the window. San Diego now sits at 7,080 lifetime permits (4.4% of state), with 2,277 in 2024 alone — a city that's quietly become the second mass-volume ADU market in the state. San Jose (3,019 lifetime, 558 in 2024), Long Beach (2,849 / 747), and Glendale (2,770 / 561) round out the top five.
Bay Area performance remains uneven. San Francisco permitted just 2,703 ADUs over twelve years, sitting at #6 — barely ahead of Garden Grove (#7, 2,203). Oakland permitted 1,913, Santa Maria 2,077. The pattern: dense single-family neighborhoods (LA, SD, Long Beach, Garden Grove, Glendale) build ADUs at scale; high-rise/townhome cities like SF struggle to convert state preemption into permit volume because the housing stock isn't garage-and-backyard.
The 2024-specific column in the table below is worth focusing on — it shows the cities accelerating fastest. LA is up 11% on its 2022 number; San Diego is up 240%; Sacramento is up 76%. The Bay Area underperforms (San Francisco's 230 in 2024 is half its 2022 number).
| # | City | Lifetime 2013–2024 | % of CA | 2024 alone | Share (vs LA) |
|---|---|---|---|---|---|
| 1 | Los Angeles | 59,118 | 36.9% | 11,404 | |
| 2 | San Diego | 7,080 | 4.4% | 2,277 | |
| 3 | San Jose | 3,019 | 1.9% | 558 | |
| 4 | Long Beach | 2,849 | 1.8% | 747 | |
| 5 | Glendale | 2,770 | 1.7% | 561 | |
| 6 | San Francisco | 2,703 | 1.7% | 230 | |
| 7 | Garden Grove | 2,203 | 1.4% | 426 | |
| 8 | Santa Maria | 2,077 | 1.3% | 435 | |
| 9 | Oakland | 1,913 | 1.2% | 213 | |
| 10 | Fullerton | 1,665 | 1.0% | 420 | |
| 11 | Sacramento | 1,564 | 1.0% | 533 | |
| 12 | Anaheim | 1,436 | 0.9% | 429 | |
| 13 | Burbank | 1,401 | 0.9% | 270 | |
| 14 | Riverside | 978 | 0.6% | 309 | |
| 15 | Torrance | 975 | 0.6% | 212 |
UC Berkeley's Center for Community Innovation graded California ADU ordinances in 2020. They evaluated 424 jurisdictions across criteria including parking requirements, owner-occupancy rules, fee structures, design review, and clarity of submittal requirements. Cities received letter grades A through F.
Cross-referencing those Scorecard grades against permit volume — including the new 2023–2024 data — produces the same nuanced result the 2022-cutoff analysis showed. A-grade cities permit more on average than D or F-grade cities, but the average is dragged upward by Los Angeles. Removing LA, the median A-grade city permits more like the median B or C city than the gap suggests on paper. The Scorecard captures whether a city has gotten out of homeowners' way procedurally, not whether homeowners want to build.
A small city with a perfect ordinance and few aging-in-place homeowners willing to add backyard rentals will have a high grade and low permit volume. A larger city with a moderately permissive ordinance, severe housing pressure, and lots of convertible garages will have a B or C grade and high permit volume. The grade is necessary — the cities that block ADUs through procedural friction can effectively zero-out adoption — but it is not sufficient.
The Scorecard predicts whether a city has built the off-ramp. It does not predict whether anyone is on the highway.
Of the 471 California cities in our merged dataset, 86 cities — almost one in five — permitted fewer than ten ADUs across the entire 2013–2024 window. 21 cities permitted exactly zero. 183 cities (39 percent of the sample) permitted fewer than fifty over twelve years.
The long tail has shrunk modestly compared to the 2022-cutoff analysis (which had 137 cities under-10 and 39 cities at zero) — but not dramatically. Most cities that were under-permitting through 2022 continue to under-permit through 2024. The +6,200-permit jump from 2022 to 2024 statewide came overwhelmingly from cities already in the top quartile growing further, not from the long tail starting to participate.
Three hypotheses still explain the long tail. First, housing-stock incompatibility: many small Central Valley and Inland Empire cities have older housing without garages or basements suitable for conversion, and lot sizes that make detached new-build economically marginal at construction costs of $300+ per square foot. Second, demographic mismatch: ADUs are disproportionately built by homeowners aged 55–75 who want a rental income stream or housing for a family member. Third, post-preemption knowledge gaps: many small-city homeowners simply do not know that state law has overridden their city's restrictive 2015-era ADU ordinance, and city planning departments — particularly those that opposed the preemption legislatively — have little incentive to publicise the new rules.
The third explanation is the only one a state housing policy can address. HCD's expanded technical-assistance program (launched 2023) and the AB 1332 pre-approved-plan framework (2025) both aim at it. Whether the 2025–2026 cohort of permits shows the long tail finally activating will be the leading indicator of whether ADUs become a statewide tool or remain an LA-plus-coastal-metros phenomenon.
The market has clearly entered its second phase. The first phase (2017–2022) was the ramp: state preemption created legal space, homeowners and builders learned the rules, and the curve compounded at +20–67% per year. The second phase (2023+) is steady-growth maturation: +10% annual growth, modest expansion of the producing-cities base, and a slowly diversifying mix of project types (detached new-builds, garage conversions, prefabs, JADUs).
The 2022-era prediction in this article's first version — "if 2021–2022 trend continues, 2023 will likely cross 30,000 and 2026 should approach 50,000" — turned out to be roughly right on 2023 (35,620 actual vs 30,000+ predicted) but is now looking optimistic for 2026. At the current +10%/year growth rate, 2026 would land closer to 47,000 than 50,000. That's still record territory, but the curve is no longer racing.
Three legislative changes still in the pipeline could re-accelerate growth. AB 1033 (ADUs separately saleable as condos in opt-in cities) is now in effect with Berkeley, SF, San Diego, San Jose, and Oakland opted in or advancing — this creates an entirely new sub-market the historical data doesn't capture yet. AB 1332 (pre-approved ADU plans, effective 2025) compresses permit timelines from 60 days to roughly 30 in cities like Burbank, Sacramento, and SD. SB 1211 (multi-family ADUs, expanded allowances) opens up a category most cities have under-utilised.
What the next dataset will not show, but that homeowners should watch, is the ratio of detached new-builds to garage conversions. The economics differ radically — a $300/sqft detached new-build at 750 sqft is a $225,000 capital project; a $150/sqft garage conversion at 400 sqft is $60,000. As construction costs continue to outpace wage growth, the conversion share will likely rise, and the absolute permit count may grow more slowly than the project-count would otherwise predict. HCD's APR data captures both as "ADU" — the granular split has to come from individual city permit records.
The biggest single-city bet for 2025–2027 is San Diego. SD permitted 2,277 ADUs in 2024 alone — already 32% of LA's 2024 number despite being a fraction of LA's population. SD's bonus-ADU programme (which allows additional units in exchange for affordability covenants) is the only programme nationally generating four-digit annual ADU growth from a non-LA city, and the next two years will tell whether it scales toward LA-equivalent volumes or plateaus at its current trajectory.
Permit data 2013–2017: Big West Coast ADU Dataset published by BuildinganADU.com (Kol Peterson), drawn from city building-department records aggregated and normalised by Karen Chapple's research team at the UC Berkeley Center for Community Innovation. The dataset's January 2024 release covers 2013–2022; we use it for 2013–2017 because HCD's APR framework didn't begin systematic ADU-line-item tracking until 2018.
Permit data 2018–2025: California HCD Housing Element Annual Progress Report (APR) Table A2, downloaded from data.ca.gov on 2026-05-01. Last refreshed by HCD on April 24, 2026. Filter: UNIT_CAT='ADU' AND BP_ISSUE_DT1 non-empty (building permit was actually issued, not just entitled). We sum the NO_BUILDING_PERMITS field per row, treating empty/0 as 1 since the permit-issue date implies a permit was issued. This matches HCD's own methodology in its public-facing APR Dashboard.
Why the source mix: our previous published numbers for 2018–2022 used the Big West Coast Dataset's January 2024 snapshot. HCD's data has been continuously refreshed since then as cities re-file with corrected counts; the 2022 figure shown in our previous version (24,851) became 31,750 in HCD's current snapshot — a 28% upward revision largely from late and corrected filings. We migrated 2018+ to HCD-current values in this refresh so the methodology is one consistent source for all post-preemption years.
2025 partial flag: 360 of an estimated 509 California jurisdictions filed by HCD's April 1, 2026 deadline. Late filings continue trickling in through mid-2026; the 25,289 figure is therefore a floor, not a final count. Charts mark 2025 with diagonal-stripe styling and an asterisk to make this explicit.
Ordinance grades: California ADU Scorecard 2020, UC Berkeley Center for Community Innovation, Appendix C. Grades reflect the legal text of each city's adopted ADU ordinance as of the 2020 evaluation. Subsequent state legislation (AB 2221, AB 976, AB 1033, AB 1332) raised the floor for every city; cities that have not updated their ordinances to reflect post-2020 state law may have effectively higher or lower grades than the Scorecard indicates depending on how much the local text now contradicts state law.
City vs county: we exclude county jurisdictions (LA County unincorporated, Alameda County unincorporated, etc.) from the city-level analysis above (top 15, long-tail counts, grade-vs-volume) because their permit-issuing geographies overlap with incorporated cities and double-count when both report. Including counties brings the statewide 2013–2024 total from 160,307 (cities only) to 180,331.
Reproducibility: all numbers in this article are computed live at build time from data/permits_ca.csv (180,331 total rows of city × year × permits). The full file is downloadable. Build-pipeline scripts (scripts/extract_permits_2023_2025.py, scripts/rebuild_permits_csv.py) are visible in the BackyardADU repository — the analysis is reproducible end-to-end.
The full extracted dataset is downloadable as CSV — 5,152 rows of city × year × permit count, covering 471 California cities and 38 county jurisdictions, 2013–2025. Cite as: "BackyardADU.net California ADU permits dataset, May 2026 release. Sources: Big West Coast ADU Dataset (2013–2017) + California HCD Annual Progress Report (2018–2025)."
If you're a journalist working on a California housing story and want underlying methodology notes, custom slices, or a specific city deep-dive, email hello@backyardadu.net. We're happy to help.
180,331 across all jurisdictions 2013–2024 (160,307 if you exclude county-unincorporated areas to avoid double-counting). 2025 partial data through HCD's April 2026 deadline adds another 25,289+ permits. This is the first public extension of the dataset past 2022.
Los Angeles, by an enormous margin — 59,118 ADUs from 2013 to 2024, about 37% of all city-issued California ADU permits in that window. The next-largest city, San Diego, permitted 7,080. LA permitted 11,404 in 2024 alone (more than its entire 2013–2018 cumulative).
Yes, on the metric they were designed to move. Statewide ADU permits jumped from 1,336 in 2016 to 5,154 in 2017 — a near-quadrupling — when SB 1069 and AB 2299 took effect. The 2019 follow-up package (SB 13, AB 68, AB 881) drove a further 67% year-over-year jump in 2019. By 2024 California was permitting 38,910 ADUs annually, a 29× increase over the 2016 baseline.
2024 — 38,910 statewide ADU permits issued (cities + county-unincorporated combined). This is a new all-time high, up 7% from 2023 and 22% from 2022. 2025 partial data (through HCD's April 1 deadline) currently shows 25,289 — late filings continue trickling in through mid-2026.
Yes, materially. Annual growth was +67% in 2019, +54% in 2021, +29% in 2022, then dropped to +12% in 2023 and +10% in 2024. The market is in its mature steady-growth phase. The 2017 and 2019 preemption-jump patterns won't repeat without new legislative shocks; the next year-over-year inflection will likely be driven by AB 1033 (saleable ADUs) or interest-rate moves rather than new state preemption.
Three reasons. First, housing-stock incompatibility — many older or smaller cities lack convertible garages or have lot sizes too small for detached new-builds at $300+/sqft construction costs. Second, demographic mismatch — ADUs are disproportionately built by homeowners aged 55–75. Third, post-preemption knowledge gaps — many homeowners and city planning departments have not yet adjusted to the fact that state law overrides previously-restrictive local ordinances. 86 of 471 California cities permitted fewer than 10 ADUs over the entire 2013–2024 window.
From /data/ — we publish the merged dataset as a 5,152-row CSV, free, MIT-licensed for any reuse with attribution. Original underlying sources: Big West Coast ADU Dataset (2013–2017) and CA HCD APR Table A2 (2018–2025).