Statistics
ADU occupancy statistics
24 of 37 figures are HyreADU calculations. The occupancy evidence belongs to one 2021 survey of a 2018–19 cohort — and this page measures how far California ADU production has moved since.
Written by HyreADU Research Desk Primary-source research and data analysis
Audited by HyreADU Research Desk Provenance and citation audit
How to use this page
Almost everything published about who lives in California ADUs traces to a single source, and it is worth naming. Karen Chapple, Dori Ganetsos and Emmanuel Lopez, Implementing the Backyard Revolution, UC Berkeley Center for Community Innovation, 22 April 2021, reviewed by the Terner Center.
It found 51% of new California ADUs generating rental income, 16% providing no-cost housing to a relative, and 8% used as short-term rentals. Those shares are theirs and are cited as theirs on every row below.
The survey frame was 2018 and 2019 permits and certificates of occupancy, fielded in 2020. That is the whole caveat, and it is a large one.
Our contribution is one join, and nothing more. California permitted 63,641 ADU units in 2024–2025 against 25,042 in the survey frame years — 2.54× as many — and the geography moved with the volume.
Across the ten jurisdictions we track most closely, the Bay Area group falls from 11.9% to 7.1% of the group while San Diego rises from 5.2% to 16.8% and Los Angeles falls from 75.0% to 55.6%.
That does not overturn the survey’s occupancy split. It states the size of the extrapolation anyone makes when they quote a 2020 survey of a 2018–19 cohort as a description of who lives in a California ADU in 2026.
No demographic profile of ADU occupants appears on this page — no age distribution, no household size, no income — because none is derivable from any dataset we can reach. The American Community Survey has no accessory-dwelling-unit flag.
24 of 37 figures on this page are HyreADU calculations (24 hyreadu calculation, 7 agency published, 6 trade / survey estimate).
What this page will not tell you
- No demographic profile of ADU occupants
There is no age distribution, household size, income, tenure length or household-composition table on this page, because no dataset we can reach supports one.
The American Community Survey does not flag accessory dwelling units; the decennial census does not; HCD’s Annual Progress Report counts units, not people.
Any published “ADU residents are typically…” claim we have traced is either survey extrapolation or invention.
- The occupancy split is one survey, and it is not ours
Every use share on this page belongs to Chapple, Ganetsos and Lopez (CCI, 22 April 2021), Terner-reviewed. It surveyed owners of ADUs permitted or completed in 2018–19, surveyed 2020. We cite it, we label it as a survey estimate, and we do not extend it, reweight it or restate it as a HyreADU finding.
- A 2021 survey is not a 2026 measurement
California permitted 2.54× as many ADU units in 2024–25 as in the survey frame years, and the geographic mix changed substantially. Whether the 51% / 16% split has held through that expansion is unknown. It might have. Nobody has measured it, and neither have we.
- What we can add: the size of the extrapolation
That is this page’s single original contribution, and it is a modest one. If you are going to quote a survey of a small, Bay-Area-heavy 2018–19 cohort as a description of a much larger, Southern-California-heavier 2026 stock, the tables below tell you exactly how large a leap you are making.
The figures most worth knowing
Full method on the who-lives-in-ADUs study. Rent behavior is on the rental-income study and its digest.
What the survey found ADUs were used for
Chapple, Ganetsos and Lopez surveyed California ADU owners in 2020 about units permitted or completed in 2018 and 2019. This is their headline result, and the single most-cited fact in California ADU policy.
The shares do not sum to 100 per cent — the categories are not exhaustive and the instrument allowed for units in none of them.
| Reported use | Share | What it implies | Class |
|---|---|---|---|
| Generating rental income | 51% | The unit is let. This is the population any rent statistic describes. | Trade / survey estimate |
| No-cost housing for a relative | 16% | A $0 rent, and a housing outcome rather than a failed investment. Roughly one unit in six. | Trade / survey estimate |
| Short-term rental | 8% | A separate regulatory question in most jurisdictions. | Trade / survey estimate |
| One-bedroom units | 61% | Why the ADU-like FMR columns are efficiency, one- and two-bedroom. | Trade / survey estimate |
| Studios | 18% | Together with one-bedrooms, close to four fifths of the surveyed stock. | Trade / survey estimate |
| Median rent among units that were let | $2,000 | A 2018–19 cohort surveyed in 2020. Not a current asking rent, and not FMR. | Trade / survey estimate |
Every row is Chapple, Ganetsos and Lopez, Implementing the Backyard Revolution, CCI, 22 April 2021 (Terner-reviewed). Cited as theirs. The 51% share is the factor the rental-income study applies as a portfolio occupancy haircut — a HyreADU calculation using Terner’s share, never a restatement of Terner’s work.
Why the 16% matters more than its size suggests. A spreadsheet that multiplies market rent by twelve and calls the result “ADU income” is wrong for that group by the whole amount, not by a margin.
Family occupancy is a $0 rent and a real housing outcome. The ROI calculator accepts $0 for exactly this reason.
How far production has moved since the survey frame
The table below is the HyreADU join, recomputed from HCD’s Annual Progress Report Table A2.
For each of the ten jurisdictions we track, the share of ADU permits in the survey frame years (2018–2019) against the share in the two most recent reported years (2024–2025). The volume grew 2.54× statewide and the mix moved with it.
| Jurisdiction | Region | 2018–19 permits | Share | 2024–25 permits | Share | Class |
|---|---|---|---|---|---|---|
| Los Angeles | Southern California | 11,895 | 75.0% | 14,701 | 55.6% | HyreADU calculation |
| San Diego | Southern California | 827 | 5.2% | 4,447 | 16.8% | HyreADU calculation |
| Unincorporated Los Angeles County | Southern California | 722 | 4.5% | 2,260 | 8.5% | HyreADU calculation |
| Long Beach | Southern California | 210 | 1.3% | 1,391 | 5.3% | HyreADU calculation |
| San José | Bay Area | 608 | 3.8% | 1,060 | 4.0% | HyreADU calculation |
| Unincorporated San Diego County | Southern California | 216 | 1.4% | 865 | 3.3% | HyreADU calculation |
| Sacramento | Central Valley | 98 | 0.6% | 725 | 2.7% | HyreADU calculation |
| Oakland | Bay Area | 532 | 3.4% | 405 | 1.5% | HyreADU calculation |
| San Francisco | Bay Area | 755 | 4.8% | 401 | 1.5% | HyreADU calculation |
| Fresno | Central Valley | 6 | 0.0% | 188 | 0.7% | HyreADU calculation |
HyreADU calculation from the HCD extract. Group totals: 15,869 permit units in 2018–19 and 26,443 in 2024–25. Statewide, 25,042 and 63,641 respectively.
These ten jurisdictions are the ones this desk tracks most closely; they are not the ten largest ADU producers in California by definition, and the shares are shares of the group rather than of the state.
2025 figures rest on APRs due 1 April 2026; HCD states prior-year data are not complete until 30 June, and this extract was retrieved after that date.
Permit counts are on an event basis — unique jurisdiction, project identifier and permit date — which is why they differ from a naive sum of APR rows. The method is on the permits-versus-completions study.
The same shift, by region
Collapsed to three regions, the movement is easier to hold in the head — and it is the specific reason a Bay-Area-heavy survey sample is a problem for a 2026 claim.
| Region | 2018–19 permits | Share of the ten | 2024–25 permits | Share of the ten | Change | Class |
|---|---|---|---|---|---|---|
| Southern California | 13,870 | 87.4% | 23,664 | 89.5% | +2.1 pts | HyreADU calculation |
| Bay Area | 1,895 | 11.9% | 1,866 | 7.1% | -4.9 pts | HyreADU calculation |
| Central Valley | 104 | 0.7% | 913 | 3.5% | +2.8 pts | HyreADU calculation |
HyreADU calculation from the HCD extract. The Bay Area group — San Francisco, Oakland and San José — falls from 11.9% to 7.1% of the ten. The CCI survey sample was Bay Area-heavy. Today’s production is not.
Why this changes the reading rather than the finding. Housing costs, household structure, lot sizes and the ordinary reasons a family builds a backyard unit differ across these regions.
A use split measured in one mix is not automatically wrong in another — but it is not automatically right either, and the honest thing is to publish the distance rather than assume it away.
Size as a constraint on who can live there
The one thing about ADU occupancy that can be measured directly is the envelope. A permit file will not say who moved in, but it says exactly how much space they moved into — and that constrains the household.
| Type | n | Median floor area | Share at or below 500 sq ft | Class |
|---|---|---|---|---|
| New-construction ADU permits | 8,536 | 920 sq ft | 14.2% | HyreADU calculation |
| Garage-conversion permits | 17,937 | 480 sq ft | — | HyreADU calculation |
| Junior ADU permits | 2,238 | 409 sq ft | 76.0% | HyreADU calculation |
HyreADU calculations over the City of Los Angeles permit extract; full frame rules on the size digest. Set against Terner/CCI’s finding that 61% of new California ADUs were one-bedroom and 18% were studios, the two evidence bases agree on the shape of the stock: small units, small households.
A junior ADU is a different housing product. Government Code § 66313 caps it at 500 square feet of interior livable space and requires it to be contained entirely within a single-family residence.
That is a unit for a family member, a lodger or a single person — and it is the type most closely associated with the 16% of units housing a relative. The junior ADU study covers what the category can and cannot be.
Where occupancy actually shows up in a decision
In a yield calculation
If 16% of units house a relative rent-free, then a portfolio expected value across a randomly chosen unit from that cohort is not market rent.
The rental-income study applies Terner’s 51% share as a haircut for exactly this reason — and says plainly that an owner who has already decided to let at market should not apply it to their own unit.
The failure is not conservatism. It is applying a population statistic to an individual decision without saying which one you are making.
In an appraisal
A capitalised rent is not an appraisal, and an ADU that houses a relative produces no rent to capitalise. Whether the unit adds value, and on what basis, is a separate question with a separate literature — see do ADUs add value.
In underwriting
Lenders have their own rules about how much accessory-unit rental income may be counted, and those rules are underwriting policy rather than a statement about occupancy. The financing study sets out the GSE treatment.
In housing policy
The 16% rent-free share is often quoted as if it were a weakness in ADU policy. It is a housing outcome: a person housed at no cost is a person housed. Whether ADU production is meeting need at scale is a different measurement, and it is on production versus housing need.
For context on scale: ADUs were 9.1% of all permits reported to HCD in 2018 and 26.1% in 2025.
Permitted is not occupied
One more caveat belongs on any occupancy page: a permit is not a household. A substantial share of permitted ADUs have no recorded completion, and an unbuilt unit houses nobody.
| Measure | Figure | Class |
|---|---|---|
| Matched permit-to-completion projects in the HCD extract | 81,853 | HyreADU calculation |
| Share of matched projects completing in the permit year | 29.4% | HyreADU calculation |
| Share of matched projects completing within one year | 78.9% | HyreADU calculation |
| Median lag from permit to completion, matched projects | 1 year | HyreADU calculation |
| 2018 permit cohort observed completion rate, seven follow-up years | 47.1% | HyreADU calculation |
| Permit units 2018–2023 with no matched completion | 46,944 of 114,651 (40.9%) | HyreADU calculation |
HyreADU calculations over the HCD Table A2 extract. Unmatched projects include units still under construction, abandoned projects, units completed without a reported certificate, and projects whose identifier changed between the permit row and the completion row. The full cohort method is on the permits-versus-completions study.
That unmatched share is a reporting artefact as much as an economic one, and we do not present it as an abandonment rate. But it is the reason “X ADUs permitted” and “X households housed” are different sentences.
Figures we will not repeat
- A demographic profile of ADU residents
Age, household size, income, tenure — none of it is derivable from a dataset we can reach. The ACS has no ADU flag, HCD counts units and not people, and the one owner survey that exists asked owners about use rather than occupants. We publish the absence.
- The 2021 survey quoted as a current measurement
It described owners of ADUs permitted or completed in 2018–19, surveyed 2020. California has since permitted 2.54× as many units, in a materially different geographic mix. Quoting “51 per cent of California ADUs are rented” in the present tense drops both the date and the frame, and both are load-bearing.
- A national ADU occupancy statistic
The survey was Californian. The permit data is Californian. There is no national ADU occupancy evidence base, and constructing one from a California survey would be the exact error this desk exists to refuse. What can be said nationally about ADUs at all is on ADUs in national permit data.
- Family occupancy described as a failure
A relative housed at no cost is a housing outcome, not a lost yield. The correct treatment is to record a $0 rent and stop, which is what our tools do. Framing one unit in six as underperforming misdescribes what those owners built the unit for.
Citing these figures
If you cite one thing from this page, cite Chapple, Ganetsos and Lopez directly. The occupancy split belongs to them, the paper is public, and it deserves the citation rather than a secondary source. Name the frame with it: owners of units permitted or completed in 2018–19, surveyed in 2020.
Where a figure is labeled HyreADU calculation, attribute it to HyreADU and name the file: “HyreADU analysis of HCD Housing Element Annual Progress Report Table A2, ADU permits by jurisdiction and year.” Where it is Agency published, cite HCD.
Link the who-lives-in-ADUs study rather than this digest — the method and the limits live there.
Carry the distance. The most useful thing this page adds is the size of the gap between the survey frame and today’s production.
A citation of the 51% figure that does not mention the year of the cohort is the failure mode; a citation that does is doing the work properly. Corrections go on the page with a dated note: hello@hyreadu.com.
Questions
Who lives in ADUs in California?
What percentage of ADUs are rented out?
How many ADUs house family members?
Is the 2021 ADU survey still accurate?
How big is a typical ADU, and what household does it hold?
Can an ADU be rented short-term?
Does the owner have to live on the property?
Do permitted ADUs actually get occupied?
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 Annual Progress Report Table A2 retrieved 2026-09-05, HCD file last updated 2026-09-04; CCI owner survey 22 April 2021; LADBS resource pi9x-tg5x analyzed 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
- Chapple, Ganetsos and Lopez, Implementing the Backyard Revolution (UC Berkeley Center for Community Innovation, 22 April 2021) , The occupancy evidence base for California ADUs, reviewed by the Terner Center. 51% income-generating; 16% rent-free to a relative; 8% short-term rental; 61% one-bedroom; 18% studio; median let rent $2,000. Survey of owners of ADUs permitted or completed in 2018–19, surveyed 2020. Cited as theirs throughout; never restated as HyreADU’s. Retrieved 2026-09-05.
- Terner Center for Housing Innovation — write-up of the CCI ADU owner survey , The same survey, Terner’s own summary. Useful for a reader who wants the finding without the full report. Retrieved 2026-09-05.
- California Department of Housing and Community Development — Housing Element Annual Progress Report, Table A2 , UNIT_CAT = 'ADU'. Permits = NO_BUILDING_PERMITS on a unique (jurisdiction, project identifier, BP_ISSUE_DT1) event, assigned to the calendar year of BP_ISSUE_DT1. Completions = NO_OTHER_FORMS_OF_READINESS on a unique (jurisdiction, project identifier, CO_ISSUE_DT1) event, assigned to the calendar year of CO_ISSUE_DT1. Identifier is JURS_TRACKING_ID when present, otherwise APN + street address. 281,321 ADU rows of 922,102 total. Every geography-shift figure on this page is computed from this extract. HCD file last updated 2026-09-04. 2025 APRs were due 1 April 2026. HCD states prior-year data are not complete until 30 June. This extract was retrieved 5 September 2026, after that date, and 2025 has slightly more Table A2 rows than 2024. Retrieved 2026-09-05.
- HCD — Housing Element Annual Progress Report data dashboard , The agency’s own presentation of the same data, for a reader who would rather not download a 900,000-row table. Retrieved 2026-09-05.
- City of Los Angeles Department of Building and Safety — Building Permits Issued from 2020 to Present (Socrata resource pi9x-tg5x) , The floor-area rows: median 920 sq ft across 8,536 new-construction ADU permits, 480 sq ft across 17,937 garage conversions, 409 sq ft across 2,238 junior ADU permits. Retrieved 2026-09-05.
- California Government Code § 66313 — definitions, including the junior ADU , “No more than 500 square feet of interior livable space … contained entirely within a single-family residence.” The statutory basis of the junior-unit rows. Retrieved 2026-09-05.
One survey, one cohort, one date
The occupancy evidence for California ADUs is a 2020 survey of a 2018–19 cohort. Quote it with its frame attached, and read the study for what it can and cannot support.
HyreADU does not design, permit or build accessory dwelling units and does not let property. Statistics are informational. They are not legal, tax, financial or construction advice.
Occupancy and use shares are the finding of Chapple, Ganetsos and Lopez (UC Berkeley Center for Community Innovation, 22 April 2021, Terner-reviewed), describe owners of units permitted or completed in 2018–19 surveyed in 2020, and are cited as theirs.
HyreADU has not surveyed ADU occupants and publishes no demographic profile of them, because no retrievable dataset supports one.
Permit and completion counts are HyreADU calculations over HCD’s Annual Progress Report Table A2 on an event basis; 2025 data rest on reports due 1 April 2026.
Floor-area figures are measurements of City of Los Angeles permit records and describe no other jurisdiction.