In short
- 229 ADU permits on record, nearly all since 2021.
- 49 in 2025, down 30% from 2024.
- Typical permit time: 229 days from application to permit (median of 68 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 |
|---|---|---|---|
| 2018 | 3 | — | — |
| 2019 | 1 | — | — |
| 2020 | 4 | — | — |
| 2021 | 16 | — | — |
| 2022 | 19 | — | — |
| 2023 | 67 | — | — |
| 2024 | 70 | — | — |
| 2025 | 49 | — | — |
“—” means the source for that year does not report ADU type.
Read more: ADU types explained
Not counted above: 46 approved projects with no building permit reported yet.
ADU rules in Buena Park
State law check: HCD found the city's 2024 ADU ordinance out of line with state law (May 28, 2025), including its limits on combining ADUs and on front-yard ADUs. The city amended it in June 2025; HCD hasn't posted a review of the update.
| Rule | Buena Park's code | State law guarantees |
|---|---|---|
| Maximum size | 850 sq ft (up to 1 bedroom) or 1,000 sq ft (2+ bedrooms), attached or detached. 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 | 16 ft; detached up to 20 ft near transit. Attached: 2 stories, up to 30 ft or the height of a two-story house, whichever is lower. | 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; existing setbacks for conversions. An ADU may go in the front setback only if it can't fit elsewhere on the lot. Second-story balconies: 5 ft. | No more than 4 ft side and rear; none for conversions of existing space. |
| Parking | 1 space per ADU unless exempt (transit, historic district, inside the house or an accessory building, permit parking, car share, built with a new home). 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: the owner lives in one of the units, with a recorded declaration. | 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 of: a conversion ADU, a new ADU or a junior ADU; or a junior ADU plus one conversion or new ADU. | 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 | 30 days or more, for ADUs and junior ADUs. | No guarantee: cities may require rentals of more than 30 days, and junior ADUs can't be short-term rentals. |
- Lots on roads narrower than the Orange County Fire Authority standard need a parking space per bedroom plus replacement parking, or a conditional use permit.
- Materials, colors and roof design must match the house; a converted garage loses its visible garage door.
- Park fees apply to ADUs of 750 sq ft or more.
Where local rules conflict with state law, state law controls. Sources: Buena Park Municipal Code 19.348.010 (Ord. 1754, June 24, 2025) · HCD findings (May 28, 2025); HCD's list of review letters; California ADU rules. Verified Oct 5, 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 | 229 | 159 – 331 | 68 |
Middle half: the range covering the middle 50% of permits (a quarter were lower, a quarter higher).
Read more: How long ADUs take to build
From permit to completion
Of the 87 ADU permits Buena Park reported issuing from 2020 through 2023, 58 (67%) have a completion reported to the state. For those, the median time from permit to completion was 8 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 Buena Park? Feature your business on this page.
Questions about ADUs in Buena Park
How many ADUs have been permitted in Buena Park?
Public records show 229 ADU permits in Buena Park through 2025, nearly all since 2021. 49 in 2025, down 30% 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 Buena Park?
Among the 68 ADU permits in Buena Park with both dates recorded, half were issued within 229 days of the application; the middle half took 159 to 331 days. That includes plan-check corrections and resubmittals, not just the review itself.
Can I build an ADU on my property in Buena Park?
California law allows ADUs on most lots with a house, including in Buena Park, 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 Buena Park?
Apply with the City of Buena Park's Planning Division, which approves qualifying ADUs without a hearing within 60 days. 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.