Statistics
ADU permit statistics
33 of 61 figures are HyreADU calculations. The California permit series year by year and jurisdiction by jurisdiction, with the counting rule stated, and the federal survey that cannot see an accessory unit at all.
Written by HyreADU Research Desk Primary-source research and data analysis
Audited by HyreADU Research Desk Provenance and figure-ledger audit
The short version
California jurisdictions reported 178,495 accessory-dwelling-unit building-permit units for 2018–2025, counted as unique permit events and assigned to the date on the permit. Annual volume went from 12,050 to 32,126, a 2.67-fold rise and a compound 15.0% a year.
The counting rule is not a detail. Sum Table A2 by APR reporting year instead, as most roundups do, and you get 213,732 — 35,237 units too many, 16.5% of the total — because jurisdictions re-report the same project across reporting years.
A published "over 200,000 California ADU permits" figure is usually that artefact rather than a finding.
Permitting is highly concentrated. The City of Los Angeles alone accounts for 27.8% of the state total; the twenty largest reporters account for 53.7% between them, leaving 82,656 units spread across everywhere else.
ADUs are now a quarter of California’s permitted housing. They went from 9.12% of all housing units permitted and reported to HCD in 2018 to 26.52% in 2024 and 26.12% in 2025.
In 2025 the state permitted 0.89 ADU units for every single-family-detached unit, against 0.26 in 2018.
None of this is visible federally. The Census Building Permits Survey has four structure categories and accessory is not one of them; an ADU created by conversion is an alteration that records no housing units at all.
In 2025 California’s own single-family-detached plus ADU total ran 9,145 units above the federal one-unit series for the state, having run 925 below it in 2018. A permit is not a building. Completions are on the main statistics digest and in the permits-vs-completions study.
33 of 61 figures below are HyreADU calculations (33 hyreadu calculation, 26 agency published, 2 trade / survey estimate).
What an ADU permit statistic can and cannot tell you
Four constraints that change the meaning of every number below.
- A permit unit is a permission, not a dwelling
Everything on this page counts permissions issued. Against these 178,495 permit units, jurisdictions have reported 102,356 certificates of occupancy, and the 2018 permit cohort’s observed completion rate is 47.1% after seven years of follow-up.
Reporting a permit count as a housing count is the most common error in this category, and it is not a small one.
- The year on the row is not the year of the permit
Table A2 is filed annually and jurisdictions re-report projects that are still live. The permit date field is what tells you when the permission was issued; the APR year tells you which filing the row appeared in.
Counting by the wrong one inflates the state total by 35,237 units. 734 ADU permit rows in this extract carry a permit date before 2018, and 50 already carry a 2026 date.
- Junior ADUs are not a category in this file
Table A2 has no JADU unit category. A junior accessory dwelling unit appears in this data only where the jurisdiction chose to code it as UNIT_CAT = ADU. So the series neither reliably includes nor reliably excludes JADUs, and no split between the two can be computed from it. See the junior-ADU page.
- Four jurisdictions cannot be counted, and are named rather than zeroed
Huntington Beach (495 ADU permits across 7 years and not one completion ever reported), Saratoga, West Sacramento and Arvin have completion fields that are unused across multiple reporting years. Their 1,069 permit units are real; their completion counts are not measurements. Every ratio on this site is published with and without them.
Where these numbers come from
California is the only state in the country with a genuine ADU permit series, and it exists as a side-effect of housing-element law rather than as a statistical program.
Every city and county must file a Housing Element Annual Progress Report; Table A2 of that report lists housing development applications and entitlements with a UNIT_CAT field, and one of its permitted values is ADU. The state publishes the combined file on data.ca.gov. This extract holds 922,102 rows, 281,321 of them coded ADU.
That provenance is a strength and a limitation at once. It is a strength because reporting is a duty, not a survey — 511 jurisdictions appear with at least one ADU permit, which is most of the state.
It is a limitation because the file is a compliance artefact assembled by hundreds of separate agencies with different permit systems, different identifier conventions and different diligence about the completion columns.
Every figure on this page carries one of three labels. HyreADU calculation means we downloaded the file and computed the figure; the method is on the permits-vs-completions study and the number here is read from the same JSON module the study reads, so the two cannot drift.
Agency published means HCD or the Census Bureau printed it. Trade / survey estimate means a named survey. 33 of the 61 figures here are ours, 26 are agency-published and 2 are survey estimates.
If you need to work with these files yourself, the California permit-data directory lists which California jurisdictions publish machine-readable permit data and what each of them actually carries.
The permit series, year by year
Permit units by the date on the permit, alongside the naive count by APR reporting year that most published totals are built from. The gap between the two columns is the double-count.
| Year | Permit units (deduplicated) | Naive, by reporting year | Difference | ADU share of all HCD permits | Class |
|---|---|---|---|---|---|
| 2018 | 12,050 | 9,000 | -3,050 | 9.12% | Agency published count · HyreADU calculation comparison |
| 2019 | 12,992 | 15,064 | +2,072 | 10.31% | Agency published count · HyreADU calculation comparison |
| 2020 | 13,116 | 16,024 | +2,908 | 11.22% | Agency published count · HyreADU calculation comparison |
| 2021 | 21,163 | 24,625 | +3,462 | 15.19% | Agency published count · HyreADU calculation comparison |
| 2022 | 26,224 | 31,813 | +5,589 | 18.49% | Agency published count · HyreADU calculation comparison |
| 2023 | 29,309 | 35,723 | +6,414 | 21.05% | Agency published count · HyreADU calculation comparison |
| 2024 | 31,515 | 39,636 | +8,121 | 26.52% | Agency published count · HyreADU calculation comparison |
| 2025 | 32,126 | 41,847 | +9,721 | 26.12% | Agency published count · HyreADU calculation comparison |
HCD APR Table A2, retrieved 2026-09-05. Deduplicated totals: 178,495 units. Naive total: 213,732. The difference of 35,237 units is 16.5% of the naive figure. Note that the naive count runs lower in the early years and much higher later — re-reporting accumulates, so the artefact grows with the age of the file.
The 2025 row is not final. 2025 APRs were due 1 April 2026 and HCD states prior-year data are not complete until 30 June; this extract was taken on 2026-09-05, after that date, and 2025 will still move a little as late filings arrive.
What the growth curve actually shows
Annual ADU permitting in California 2.67-folded between 2018 and 2025, from 12,050 units to 32,126 — a compound 15.0% a year. But the curve is not a smooth ramp, and the shape is the interesting part.
Three years are almost flat: 12,050 in 2018, 12,992 in 2019, 13,116 in 2020.
Then two years of very steep growth — 21,163 in 2021 and 26,224 in 2022, an increase of 13,108 units in two years. Then a decelerating climb: 29,309, 31,515, 32,126.
The 2024-to-2025 increase is 1.9%, the smallest year-on-year move in the series apart from the flat opening.
What this page will not do is attribute that shape to a named statute. The temptation is strong — the acceleration sits close to several reform waves — but permit dates lag legislative effective dates by an unmeasured amount, jurisdictions adopt implementing ordinances on their own schedules, and the same years contain a pandemic, an interest-rate cycle and a construction-cost shock.
A correlation between a curve and a bill number is not a causal finding, and we do not have the design that would produce one.
The comparison that is clean sits inside the same file. In 2018 California permitted 0.26 ADU units for every single-family-detached unit. In 2025 it permitted 0.89.
Single-family-detached permitting fell over the period — 45,928 units to 35,424 — while ADU permitting rose, so the ratio moved from both ends.
That is a statement about the composition of Californian housing production, and it does not require anyone to attribute causation.
Permits by jurisdiction: the twenty largest reporters
The distribution is extremely long-tailed. One city accounts for 27.8% of all California ADU permitting; the twentieth-largest reporter is smaller than the largest by a factor of 48.
| Jurisdiction | County | Permit units | Share of state total | Years reporting permits | Class |
|---|---|---|---|---|---|
| Los Angeles | Los Angeles | 49,556 | 27.8% | 8 | Agency published count · HyreADU calculation share |
| San Diego | San Diego | 9,153 | 5.1% | 8 | Agency published count · HyreADU calculation share |
| Unincorporated Los Angeles County | Los Angeles | 5,657 | 3.2% | 8 | Agency published count · HyreADU calculation share |
| Long Beach | Los Angeles | 3,493 | 2.0% | 8 | Agency published count · HyreADU calculation share |
| San José | Santa Clara | 3,337 | 1.9% | 8 | Agency published count · HyreADU calculation share |
| Santa Maria | Santa Barbara | 2,554 | 1.4% | 8 | Agency published count · HyreADU calculation share |
| Garden Grove | Orange | 2,477 | 1.4% | 8 | Agency published count · HyreADU calculation share |
| San Francisco | San Francisco | 2,353 | 1.3% | 8 | Agency published count · HyreADU calculation share |
| Unincorporated San Diego County | San Diego | 2,274 | 1.3% | 8 | Agency published count · HyreADU calculation share |
| Oakland | Alameda | 1,891 | 1.1% | 8 | Agency published count · HyreADU calculation share |
| Glendale | Los Angeles | 1,777 | 1.0% | 8 | Agency published count · HyreADU calculation share |
| Burbank | Los Angeles | 1,762 | 1.0% | 8 | Agency published count · HyreADU calculation share |
| Sacramento | Sacramento | 1,631 | 0.9% | 8 | Agency published count · HyreADU calculation share |
| Anaheim | Orange | 1,292 | 0.7% | 8 | Agency published count · HyreADU calculation share |
| Riverside | Riverside | 1,185 | 0.7% | 8 | Agency published count · HyreADU calculation share |
| Unincorporated Santa Barbara County | Santa Barbara | 1,144 | 0.6% | 8 | Agency published count · HyreADU calculation share |
| Santa Ana | Orange | 1,120 | 0.6% | 8 | Agency published count · HyreADU calculation share |
| Chula Vista | San Diego | 1,109 | 0.6% | 8 | Agency published count · HyreADU calculation share |
| Westminster | Orange | 1,037 | 0.6% | 8 | Agency published count · HyreADU calculation share |
| Pasadena | Los Angeles | 1,037 | 0.6% | 8 | Agency published count · HyreADU calculation share |
HCD APR Table A2, 2018–2025, retrieved 2026-09-05. Counts are agency-published; the share column is ours. Together these twenty jurisdictions account for 95,839 permit units, 53.7% of the state total. The four unusable reporters are excluded from this table and named separately.
Three of the twenty are unincorporated county areas rather than cities — unincorporated Los Angeles County, unincorporated San Diego County and unincorporated Santa Barbara County. County and city rows are not nested: a county row covers only the unincorporated territory, so adding a county to its cities does not double-count.
How concentrated the permitting is
Three tiers, one state. The tail matters because policy discussion about ADUs is largely conducted in the language of the head.
| Tier | Permit units | Share of state total | Class |
|---|---|---|---|
| City of Los Angeles | 49,556 | 27.8% | HyreADU calculation |
| Jurisdictions ranked 2–20 | 46,283 | 25.9% | HyreADU calculation |
| Every other reporting jurisdiction | 82,656 | 46.3% | HyreADU calculation |
| All California | 178,495 | 100% | Agency published total |
HyreADU calculation on HCD APR Table A2, retrieved 2026-09-05. 511 jurisdictions reported at least one ADU permit in the window; the median of the top twenty is 1,777 units, and the great majority of reporting jurisdictions are far below that.
Concentration inside a city is a separate and equally strong pattern. In Los Angeles, 53.8% of ADU permits are in the San Fernando Valley and the Gini coefficient across census tracts holding at least one permit is 0.4731 — see the geography study.
Against the federal permit series, year by year
The Census Building Permits Survey is the number the country actually uses to talk about housing production, and it cannot see an accessory dwelling unit. It classifies buildings into four structure types — single-family, two-unit, three-and-four-unit, and five-or-more — and none is accessory.
A detached new-build ADU lands in the single-family cell beside a four-bedroom spec house. A garage conversion is an alteration under Item 434, which records permits and valuation and no housing units at all.
The comparison below sets California’s own single-family-detached-plus-ADU total against the federal one-unit series for the same state and year. It is a HyreADU calculation and it demonstrates the size of the gap; it does not validate either series.
| Year | HCD ADU | HCD single-family detached | HCD SFD + ADU | Federal 1-unit | Difference | Class |
|---|---|---|---|---|---|---|
| 2018 | 11,978 | 45,928 | 57,906 | 58,831 | -925 | Agency published counts · HyreADU calculation difference |
| 2019 | 12,865 | 43,452 | 56,317 | 58,575 | -2,258 | Agency published counts · HyreADU calculation difference |
| 2020 | 12,947 | 40,862 | 53,809 | 59,043 | -5,234 | Agency published counts · HyreADU calculation difference |
| 2021 | 20,843 | 50,983 | 71,826 | 65,890 | +5,936 | Agency published counts · HyreADU calculation difference |
| 2022 | 25,826 | 39,914 | 65,740 | 63,628 | +2,112 | Agency published counts · HyreADU calculation difference |
| 2023 | 28,906 | 39,480 | 68,386 | 58,534 | +9,852 | Agency published counts · HyreADU calculation difference |
| 2024 | 31,006 | 34,979 | 65,985 | 61,143 | +4,842 | Agency published counts · HyreADU calculation difference |
| 2025 | 31,460 | 35,424 | 66,884 | 57,739 | +9,145 | Agency published counts · HyreADU calculation difference |
HCD Housing Element APR, Table A2, retrieved 2026-09-05; U.S. Census Bureau, Building Permits Survey, annual 2025 release (14 May 2026), California column, units.
The two series are built to different definitions, cover slightly different universes and are collected by different means.
The difference column is a HyreADU calculation and is a measure of the distance between the two instruments, not an error term for either.
The direction of the difference reverses. In 2018 the state total ran 925 units below the federal one-unit series; by 2025 it ran 9,145 units above. Over the same eight years the federal one-unit line for California moved by -1.9% while California’s ADU permits rose 2.67-fold. Full mechanics on the national-permit-data study.
The words this data uses, precisely
- Permit unit
- One dwelling unit authorized by a building permit. A single permit can authorize more than one unit, and the ADU rows in Table A2 carry a unit count, so the state total is a count of units rather than of permits.
- Permit event
- A unique combination of jurisdiction, project identifier and building-permit date. Deduplicating to events is what turns 281,321 ADU rows into 169,249 permit events and prevents the same project being counted in successive annual reports.
- APR year
- The reporting year of the filing a row appeared in — not the year the permit was issued. Using it as a permit date is the single most common counting error with this file.
- UNIT_CAT
- Table A2’s unit-category field. Values in this extract: ADU, SFD (single-family detached), SFA (single-family attached), 2 to 4, 5+, MH (mobile home). There is no JADU value.
- Tracking identifier
- The jurisdiction’s own project identifier, used to join a permit row to a completion row. 15,082 ADU rows (5.4%) carry none and cannot be joined in either direction.
- Item 434
- The line in the federal Building Permits Survey that collects additions and alterations to residential buildings. It records a permit count and a valuation and carries no housing-unit field, which is why a conversion ADU is federally invisible.
Every figure on this page, with its class
61 figures with geography, date, provenance class and source. 33 HyreADU calculations, 26 agency-published, 2 trade or survey. This is the list the one-third hub gate counts.
| Statistic | Figure | Geography | Date | Class | Source |
|---|---|---|---|---|---|
| ADU permit units dated 2018 | 12,050 | California, 511 reporting jurisdictions | 2018 | Agency published | HCD Housing Element APR, Table A2, retrieved 2026-09-05 |
| ADU permit units dated 2019 | 12,992 | California, 511 reporting jurisdictions | 2019 | Agency published | HCD Housing Element APR, Table A2, retrieved 2026-09-05 |
| ADU permit units dated 2020 | 13,116 | California, 511 reporting jurisdictions | 2020 | Agency published | HCD Housing Element APR, Table A2, retrieved 2026-09-05 |
| ADU permit units dated 2021 | 21,163 | California, 511 reporting jurisdictions | 2021 | Agency published | HCD Housing Element APR, Table A2, retrieved 2026-09-05 |
| ADU permit units dated 2022 | 26,224 | California, 511 reporting jurisdictions | 2022 | Agency published | HCD Housing Element APR, Table A2, retrieved 2026-09-05 |
| ADU permit units dated 2023 | 29,309 | California, 511 reporting jurisdictions | 2023 | Agency published | HCD Housing Element APR, Table A2, retrieved 2026-09-05 |
| ADU permit units dated 2024 | 31,515 | California, 511 reporting jurisdictions | 2024 | Agency published | HCD Housing Element APR, Table A2, retrieved 2026-09-05 |
| ADU permit units dated 2025 | 32,126 | California, 511 reporting jurisdictions | 2025 | Agency published | HCD Housing Element APR, Table A2, retrieved 2026-09-05 |
| ADU permit units, whole window | 178,495 | California, 511 reporting jurisdictions | 2018–2025 | Agency published | HCD Housing Element APR, Table A2, retrieved 2026-09-05 |
| Table A2 rows in the extract | 922,102 | California, all unit categories | 2018–2025 | Agency published | HCD Housing Element APR, Table A2, retrieved 2026-09-05 |
| Rows with UNIT_CAT = ADU | 281,321 | California, 511 reporting jurisdictions | 2018–2025 | Agency published | HCD Housing Element APR, Table A2, retrieved 2026-09-05 |
| Unique ADU permit events after deduplication | 169,249 | California, 511 reporting jurisdictions | 2018–2025 | Agency published | HCD Housing Element APR, Table A2, retrieved 2026-09-05 |
| Jurisdictions reporting at least one ADU permit | 511 | California | 2018–2025 | Agency published | HCD Housing Element APR, Table A2, retrieved 2026-09-05 |
| Single-family-detached permit units for comparison | 35,424 | California, 511 reporting jurisdictions | 2025 | Agency published | HCD Housing Element APR, Table A2, retrieved 2026-09-05 |
| All housing permit units reported to HCD | 120,455 | California, 511 reporting jurisdictions | 2025 | Agency published | HCD Housing Element APR, Table A2, retrieved 2026-09-05 |
| California 1-unit permit units, federal series, 2018 | 58,831 | California | 2018 | Agency published | U.S. Census Bureau, Building Permits Survey, annual 2025 release (14 May 2026) |
| California 1-unit permit units, federal series, 2019 | 58,575 | California | 2019 | Agency published | U.S. Census Bureau, Building Permits Survey, annual 2025 release (14 May 2026) |
| California 1-unit permit units, federal series, 2020 | 59,043 | California | 2020 | Agency published | U.S. Census Bureau, Building Permits Survey, annual 2025 release (14 May 2026) |
| California 1-unit permit units, federal series, 2021 | 65,890 | California | 2021 | Agency published | U.S. Census Bureau, Building Permits Survey, annual 2025 release (14 May 2026) |
| California 1-unit permit units, federal series, 2022 | 63,628 | California | 2022 | Agency published | U.S. Census Bureau, Building Permits Survey, annual 2025 release (14 May 2026) |
| California 1-unit permit units, federal series, 2023 | 58,534 | California | 2023 | Agency published | U.S. Census Bureau, Building Permits Survey, annual 2025 release (14 May 2026) |
| California 1-unit permit units, federal series, 2024 | 61,143 | California | 2024 | Agency published | U.S. Census Bureau, Building Permits Survey, annual 2025 release (14 May 2026) |
| California 1-unit permit units, federal series, 2025 | 57,739 | California | 2025 | Agency published | U.S. Census Bureau, Building Permits Survey, annual 2025 release (14 May 2026) |
| Structure categories in the federal survey | 4 | United States | current methodology | Agency published | Census BPS methodology — none of the four is accessory |
| Housing units the federal survey records for a conversion ADU | 0 | United States | current methodology | Agency published | Census BPS Item 434 carries no housing-unit field |
| ADU permit units, unincorporated San Diego County | 1,617 | Unincorporated San Diego County | 6th cycle to 2025 | Agency published | HCD RHNA Progress Report, 6th cycle, retrieved 2026-09-05 |
| Growth in annual permit units, 2018 to 2025 | 2.67× | California, 511 reporting jurisdictions | 2018→2025 | HyreADU calculation | HCD Housing Element APR, Table A2, retrieved 2026-09-05 · permits-vs-completions study |
| Compound annual growth in permit units | 15.0% | California, 511 reporting jurisdictions | 2018–2025 | HyreADU calculation | HCD Housing Element APR, Table A2, retrieved 2026-09-05 · permits-vs-completions study |
| Permit units added between 2020 and 2022 | +13,108 | California, 511 reporting jurisdictions | 2020→2022 | HyreADU calculation | HCD Housing Element APR, Table A2, retrieved 2026-09-05 · permits-vs-completions study |
| Change in annual permit units, 2024 to 2025 | +1.9% | California, 511 reporting jurisdictions | 2024→2025 | HyreADU calculation | HCD Housing Element APR, Table A2, retrieved 2026-09-05 · permits-vs-completions study |
| ADU share of all HCD-reported permit units, 2018 | 9.12% | California, 511 reporting jurisdictions | 2018 | HyreADU calculation | HCD Housing Element APR, Table A2, retrieved 2026-09-05 · permits-vs-completions study |
| ADU share of all HCD-reported permit units, 2024 | 26.52% | California, 511 reporting jurisdictions | 2024 | HyreADU calculation | HCD Housing Element APR, Table A2, retrieved 2026-09-05 · permits-vs-completions study |
| ADU share of all HCD-reported permit units, 2025 | 26.12% | California, 511 reporting jurisdictions | 2025 | HyreADU calculation | HCD Housing Element APR, Table A2, retrieved 2026-09-05 · permits-vs-completions study |
| ADU permits relative to single-family-detached permits, 2025 | 0.89× | California, 511 reporting jurisdictions | 2025 | HyreADU calculation | HCD Housing Element APR, Table A2, retrieved 2026-09-05 · permits-vs-completions study |
| Same ratio in 2018 | 0.26× | California, 511 reporting jurisdictions | 2018 | HyreADU calculation | HCD Housing Element APR, Table A2, retrieved 2026-09-05 · permits-vs-completions study |
| Permit units double-counted by a naive APR-reporting-year sum | 35,237 | California, 511 reporting jurisdictions | 2018–2025 | HyreADU calculation | HCD Housing Element APR, Table A2, retrieved 2026-09-05 · permits-vs-completions study |
| Share of a naive permit total that is double-counted | 16.5% | California, 511 reporting jurisdictions | 2018–2025 | HyreADU calculation | HCD Housing Element APR, Table A2, retrieved 2026-09-05 · permits-vs-completions study |
| Naive APR-year permit total, for contrast | 213,732 | California, 511 reporting jurisdictions | 2018–2025 | HyreADU calculation | HCD Housing Element APR, Table A2, retrieved 2026-09-05 · permits-vs-completions study |
| ADU rows carrying no tracking identifier | 15,082 (5.4%) | California, 511 reporting jurisdictions | 2018–2025 | HyreADU calculation | HCD Housing Element APR, Table A2, retrieved 2026-09-05 · permits-vs-completions study |
| Permit units reported by the four unusable reporters | 1,069 | Huntington Beach, Saratoga, West Sacramento, Arvin | 2018–2025 | HyreADU calculation | HCD Housing Element APR, Table A2, retrieved 2026-09-05 · permits-vs-completions study |
| Permit units after excluding those four | 177,426 | California, 511 reporting jurisdictions | 2018–2025 | HyreADU calculation | HCD Housing Element APR, Table A2, retrieved 2026-09-05 · permits-vs-completions study |
| Los Angeles share of all California ADU permit units | 27.8% | City of Los Angeles | 2018–2025 | HyreADU calculation | HCD Housing Element APR, Table A2, retrieved 2026-09-05 · permits-vs-completions study |
| Top-20 jurisdictions’ share of all California ADU permit units | 53.7% | California | 2018–2025 | HyreADU calculation | HCD Housing Element APR, Table A2, retrieved 2026-09-05 · permits-vs-completions study |
| Permit units outside the top twenty jurisdictions | 82,656 | California | 2018–2025 | HyreADU calculation | HCD Housing Element APR, Table A2, retrieved 2026-09-05 · permits-vs-completions study |
| Median permit units among the top twenty | 1,777 | California | 2018–2025 | HyreADU calculation | HCD Housing Element APR, Table A2, retrieved 2026-09-05 · permits-vs-completions study |
| HCD single-family-detached plus ADU minus the federal 1-unit series, 2018 | -925 units | California | 2018 | HyreADU calculation | HCD Housing Element APR, Table A2, retrieved 2026-09-05 against U.S. Census Bureau, Building Permits Survey, annual 2025 release (14 May 2026) · national-permit-data study |
| HCD single-family-detached plus ADU minus the federal 1-unit series, 2019 | -2,258 units | California | 2019 | HyreADU calculation | HCD Housing Element APR, Table A2, retrieved 2026-09-05 against U.S. Census Bureau, Building Permits Survey, annual 2025 release (14 May 2026) · national-permit-data study |
| HCD single-family-detached plus ADU minus the federal 1-unit series, 2020 | -5,234 units | California | 2020 | HyreADU calculation | HCD Housing Element APR, Table A2, retrieved 2026-09-05 against U.S. Census Bureau, Building Permits Survey, annual 2025 release (14 May 2026) · national-permit-data study |
| HCD single-family-detached plus ADU minus the federal 1-unit series, 2021 | +5,936 units | California | 2021 | HyreADU calculation | HCD Housing Element APR, Table A2, retrieved 2026-09-05 against U.S. Census Bureau, Building Permits Survey, annual 2025 release (14 May 2026) · national-permit-data study |
| HCD single-family-detached plus ADU minus the federal 1-unit series, 2022 | +2,112 units | California | 2022 | HyreADU calculation | HCD Housing Element APR, Table A2, retrieved 2026-09-05 against U.S. Census Bureau, Building Permits Survey, annual 2025 release (14 May 2026) · national-permit-data study |
| HCD single-family-detached plus ADU minus the federal 1-unit series, 2023 | +9,852 units | California | 2023 | HyreADU calculation | HCD Housing Element APR, Table A2, retrieved 2026-09-05 against U.S. Census Bureau, Building Permits Survey, annual 2025 release (14 May 2026) · national-permit-data study |
| HCD single-family-detached plus ADU minus the federal 1-unit series, 2024 | +4,842 units | California | 2024 | HyreADU calculation | HCD Housing Element APR, Table A2, retrieved 2026-09-05 against U.S. Census Bureau, Building Permits Survey, annual 2025 release (14 May 2026) · national-permit-data study |
| HCD single-family-detached plus ADU minus the federal 1-unit series, 2025 | +9,145 units | California | 2025 | HyreADU calculation | HCD Housing Element APR, Table A2, retrieved 2026-09-05 against U.S. Census Bureau, Building Permits Survey, annual 2025 release (14 May 2026) · national-permit-data study |
| HCD all-permit total over the federal all-structure total, 2025 | 1.160× | California | 2025 | HyreADU calculation | HCD Housing Element APR, Table A2, retrieved 2026-09-05 against U.S. Census Bureau, Building Permits Survey, annual 2025 release (14 May 2026) · national-permit-data study |
| Federal 1-unit series change, 2018 to 2025, while ADU permits went up 2.67× | -1.9% | California | 2018→2025 | HyreADU calculation | HCD Housing Element APR, Table A2, retrieved 2026-09-05 against U.S. Census Bureau, Building Permits Survey, annual 2025 release (14 May 2026) · national-permit-data study |
| Permit rows dated before the reporting window | 734 | California, 511 reporting jurisdictions | pre-2018 dates | HyreADU calculation | HCD Housing Element APR, Table A2, retrieved 2026-09-05 · permits-vs-completions study |
| Permit rows already dated 2026 | 50 | California, 511 reporting jurisdictions | 2026 dates | HyreADU calculation | HCD Housing Element APR, Table A2, retrieved 2026-09-05 · permits-vs-completions study |
| Median declared permit valuation, Los Angeles | $40,000 | City of Los Angeles | 2017–2023 issued | HyreADU calculation | Municipal permit harvests 29–30 August 2026, computed 2026-09-05 · permit-valuation study |
| Median declared permit valuation, unincorporated Marin | $156,800 | Marin County (unincorporated) | 2014–2026 issued | HyreADU calculation | Municipal permit harvests 29–30 August 2026, computed 2026-09-05 · permit-valuation study |
| New California ADUs that are one-bedroom | 61% | California, 2018–19 owner survey | Apr 2021 | Trade / survey estimate | Chapple, Ganetsos and Lopez, CCI, 22 April 2021 |
| New California ADUs that are studios | 18% | California, 2018–19 owner survey | Apr 2021 | Trade / survey estimate | Chapple, Ganetsos and Lopez, CCI, 22 April 2021 |
HyreADU calculation — computed by HyreADU from a primary file, method on the linked study. Agency published — printed by HCD or the Census Bureau. Trade / survey estimate — a named survey estimate. HCD and RHNA extracts retrieved 2026-09-05.
Permit figures we will not repeat
- An inflated California permit total taken from a naive sum
Summing Table A2 by reporting year gives 213,732 permit units for 2018–2025 against a deduplicated 178,495. Both figures come from the same official file; only one of them counts each permission once. If a published total is above about 180,000 for this window, check the counting rule before citing it.
- A national ADU permit count
There is no such number and no federal instrument that could produce one without a change to the survey form. Anything presented as a national ADU permit count is either a state series relabelled or an extrapolation from California, which assumes the rest of the country has California’s statute. It does not.
- A JADU-versus-ADU split derived from this file
Table A2 has no junior-ADU category. Junior units appear only where a jurisdiction chose to code them as ADU, so the file supports neither a JADU count nor a clean ADU count net of JADUs. Any split quoted from this source is invented.
- A jurisdiction league table dressed up as performance
The counts below are volume, and volume tracks population, housing stock and lot geometry before it tracks policy. A city with 1,037 permits is not failing relative to one with 49,556.
Per-capita or per-parcel normalisation would be the right instrument and this desk has not computed one it is prepared to defend, so it does not publish one.
Citing these figures
Cite the permits-vs-completions study rather than this digest where you can: the counting rule, the sensitivity checks and the unusable-reporter classification live there, and the figure travels better with them attached.
For anything labeled HyreADU calculation, attribute it as "HyreADU analysis of the California HCD Housing Element Annual Progress Report, Table A2, retrieved 5 September 2026".
For anything labeled Agency published, cite HCD or the Census Bureau and link the table, not an article about the table. Corrections go on the page with a dated note: hello@hyreadu.com.
Questions
How many ADU permits does California issue each year?
Why do other sites report a much higher California ADU permit total?
Which city issues the most ADU permits in California?
What share of California housing permits are ADUs?
Are there national ADU permit statistics?
Do these figures include junior ADUs?
What is a permit unit worth in declared valuation terms?
How long does it take to get one of these permits issued?
How current is this data and when does it change?
Can permit counts tell me whether ADUs are being built?
Written and audited by
HyreADU Research Desk
Primary-source research, data analysis and fact checking
We are a research desk, not a builder. We read the permit extract, the statute, the HCD return or the fee schedule ourselves, and publish each figure with its source and retrieval date.
Where a number cannot be traced to a primary source, we leave it out and say what we could not verify. Our store-based claims cover California only.
- CA
- the only state this desk will make store-based claims about
- 5
- jurisdictions with extracted ADU permit evidence
- 735
- CSLB-verified companies in the California store
- 0
- national claims from a one-state store
How this desk works
- Primary sources only. Permit counts come from the city or county that issued the permit. Production counts come from HCD’s Annual Progress Report. Rents come from HUD or the Census. We do not cite an article that cites a source; we download the source and compute the figure ourselves.
- This is a California site. The company store is 734 California firms and one New Mexico firm. Permit evidence exists for five named jurisdictions: Los Angeles, San Francisco, Sacramento, San José and unincorporated Marin. A number from that store is titled to those places, never to the United States.
- A permit is not a completion, and a license is not an ADU grade. California licenses no ADU classification. Being named on an ADU permit is evidence of engagement in that jurisdiction, not of quality, completion, or work anywhere else. Owner-builder permits are excluded from contractor counts.
- Calculation is labeled as calculation. Figures we derive are never presented as something HCD, HUD, the Census or a city published. Terner Center research is cited as Terner’s, never restated as ours.
- We do not design, permit or build ADUs, and we take no payment for placement, ranking or a favorable mention. Pages that look like rankings are not: they publish public-record counts and let the reader decide.
- Nothing here is legal, tax or financial advice. Zoning, underwriting and appraisal practice vary by jurisdiction, lender and appraiser. The useful next step on a specific lot is the planning counter and a licensed professional.
Data as of HCD APR Table A2 retrieved 2026-09-05; HCD last updated 4 September 2026 (15:44 UTC); Census BPS annual 2025 release 14 May 2026; RHNA Progress Report retrieved 2026-09-05. Authorship on this site is organizational: the analysis belongs to the desk rather than to a named individual, and we do not publish credentials we do not hold.
Our editorial policy sets out how we source, date and correct what we publish.
Sources & retrieval dates
- California HCD — Housing Element Annual Progress Report, Table A2 , 922,102 rows in this extract, 281,321 coded UNIT_CAT = ADU, resolving to 169,249 unique permit events. HCD last updated 4 September 2026. Retrieved 2026-09-05.
- California HCD — Table A2 CSV download , The file itself, so every count on this page can be reproduced. Retrieved 2026-09-05.
- California HCD — APR data dashboard , HCD’s own visualisation of the same file, useful as a cross-check on any figure here. Retrieved 2026-09-05.
- California HCD — Annual Progress Report FAQ , HCD’s statement that prior-year data are not complete until 30 June, and its guidance to jurisdictions on completing Table A2. Retrieved 2026-09-05.
- U.S. Census Bureau — Building Permits Survey, annual history by state and territory , California column, units. U.S. Census Bureau, Building Permits Survey, annual 2025 release (14 May 2026). The federal one-unit series used in the comparison table. Retrieved 2026-09-05.
- U.S. Census Bureau — Building Permits Survey methodology , The four structure categories, and the Item 434 definition that leaves conversion ADUs with no unit count. Retrieved 2026-09-05.
- California HCD — RHNA Progress Report, 6th cycle , Cycle-to-date permitted units by jurisdiction, used for the housing-supply cross-reference. Retrieved 2026-09-05.
- Terner Center — “Reaching California’s ADU Potential” , Contemporaneous APR snapshots for 2018 and 2019. Later APRs backfill earlier permit dates, which is why our 2018 event-year count is higher than Terner’s; the discrepancy is a property of the file, not a disagreement. Retrieved 2026-09-05.
A permit is a permission, not a building
178,495 permit units, 102,356 certificates. Both numbers are real and they answer different questions. Read the production study before quoting either.
HyreADU does not design, permit or build accessory dwelling units. These statistics are informational and are not legal, tax, financial or construction advice. Every figure here describes California; there is no national ADU permit series and nothing on this page is scaled into one.
A permit unit is a permission, not a completed dwelling. Jurisdiction counts are volume, not performance. Table A2 is a compliance artefact assembled by hundreds of agencies and its completion fields are unusable in four named jurisdictions.