In short
- 551 ADU permits since 2018.
- 96 in 2025, down 36% from 2024.
- Typical permit time: 182 days from application to permit (median of 279 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 | 15 | 0 | 1 |
| 2019 | 12 | 0 | 1 |
| 2020 | 41 | 5 | 12 |
| 2021 | 56 | 8 | 34 |
| 2022 | 88 | 30 | 24 |
| 2023 | 93 | 22 | 45 |
| 2024 | 150 | 8 | 11 |
| 2025 | 96 | — | — |
“—” means the source for that year does not report ADU type.
Read more: ADU types explained
Not counted above: 139 approved projects with no building permit reported yet.
ADU rules in Orange
State law check: HCD found the city's 2021 ADU ordinance out of line with state law (October 11, 2022); the city amended it July 23, 2024, and no HCD letter on the update is on file.
| Rule | Orange's code | State law guarantees |
|---|---|---|
| Maximum size | 850 sq ft (studio or 1 bedroom) or 1,000 sq ft (2+ bedrooms), and no more than 50% of the house (at least 800 sq ft). Conversions keep the existing size (plus 150 sq ft for access). 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: 16 ft (18 ft near transit, plus 2 ft for roof pitch). Attached: 25 ft or the zone limit, 2 stories. | 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 | Up to 800 sq ft: 4 ft side and rear, front setback of the zone. Over 800 sq ft: the zone's setbacks. None for conversions. | No more than 4 ft side and rear; none for conversions of existing space. |
| Parking | 1 space per ADU or per bedroom, whichever is less, unless exempt (transit, historic district, car share, inside existing space). Junior ADU: none, but lost parking for the house is replaced. | 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 (the code's 2025 rule applied only if state law lapsed; state law now bars it). Junior ADU: the owner lives in the house or the junior ADU. | 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 ADU (attached, detached or converted) and one junior ADU on a single-family lot. | 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 | More than 30 days, 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. |
- Objective design standards apply: at least two materials and two colors, trim around windows and doors, and a roof that matches the house.
- Historic districts and listed historic homes: their design standards apply, and garage doors on contributing buildings must stay in place.
- ADUs over 800 sq ft must meet the zone's open space rules.
- Planning reviews an ADU application first, then the building plan check follows.
Where local rules conflict with state law, state law controls. Sources: Orange Municipal Code 17.29 · HCD findings (October 11, 2022); 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 |
|---|---|---|---|
| Detached ADU | 222 | 149 – 347 | 92 |
| Attached ADU | 238 | 172 – 304 | 27 |
| Garage conversion | 178 | 120 – 278 | 48 |
| Junior ADU (JADU) | too few to say | 2 | |
| Unclassified | 162 | 110 – 232 | 110 |
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 238 ADU permits Orange reported issuing from 2020 through 2023, 115 (48%) 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 Orange? Feature your business on this page.
Questions about ADUs in Orange
How many ADUs have been permitted in Orange?
Public records show 551 ADU permits in Orange from 2018 through 2025. 96 in 2025, down 36% 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 Orange?
Among the 279 ADU permits in Orange with both dates recorded, half were issued within 182 days of the application; the middle half took 128 to 278 days. That includes plan-check corrections and resubmittals, not just the review itself.
Can I build an ADU on my property in Orange?
California law allows ADUs on most lots with a house, including in Orange, 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 Orange?
Apply with the City of Orange's Planning Division, which reviews an ADU application before the building plan check. 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.