In short
- 100 ADU permits on record, nearly all since 2018.
- 25 in 2025.
- Typical permit time: 179 days from application to permit (median of 46 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 |
|---|---|---|---|
| 2017 (partial records) | 1 | — | — |
| 2018 | 7 | — | — |
| 2019 | 11 | — | — |
| 2020 | 9 | — | — |
| 2021 | 13 | 0 | 2 |
| 2022 | 7 | 0 | 1 |
| 2023 | 16 | 0 | 2 |
| 2024 | 11 | 0 | 4 |
| 2025 | 25 | 0 | 9 |
“—” means the source for that year does not report ADU type.
Read more: ADU types explained
Not counted above: 1 approved projects with no building permit reported yet.
ADU rules in Brea
State law check: No HCD review letter on file; that is not a finding of compliance.
| Rule | Brea's code | State law guarantees |
|---|---|---|
| Maximum size | Detached: 1,200 sq ft. Attached: 50% of the house or 1,200 sq ft, whichever is less, but at least 850 sq ft (1 bedroom) or 1,000 sq ft (2+ bedrooms). No cap for conversions. 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, plus the extra height state law allows near transit and for roof pitch. Attached: 25 ft or the zone limit, 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; front per the zone, reduced if needed for an 800 sq ft ADU. A detached ADU can't sit closer to the street than the house's front wall and must be 10 ft from the house. | No more than 4 ft side and rear; none for conversions of existing space. |
| Parking | 1 space, tandem allowed, unless exempt (transit, historic district, inside existing space, permit parking, car share). No replacement parking. Junior ADU: none. | 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 that shares a bathroom: the owner lives on site, with a recorded covenant. | 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 conversion ADU, one new detached or attached ADU and one junior 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 consecutive 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. |
- ADUs are reviewed ministerially through building plan check, with no hearing.
- A design that doesn't meet the standards table can ask for a Certificate of Compatibility.
- The city updated its ADU chapter on June 16, 2026.
Where local rules conflict with state law, state law controls. Sources: Brea City Code chapter 20.52 (amended June 16, 2026) · Brea City Code 20.08.040 (parking); 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 | 216 | 162 – 260 | 15 |
| Attached ADU | 230 | 111 – 282 | 17 |
| Junior ADU (JADU) | too few to say | 5 | |
| Unclassified | too few to say | 9 |
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 45 ADU permits Brea reported issuing from 2020 through 2023, 31 (69%) 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 Brea? Feature your business on this page.
Questions about ADUs in Brea
How many ADUs have been permitted in Brea?
Public records show 100 ADU permits in Brea through 2025, nearly all since 2018. 25 in 2025. 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 Brea?
Among the 46 ADU permits in Brea with both dates recorded, half were issued within 179 days of the application; the middle half took 114 to 271 days. That includes plan-check corrections and resubmittals, not just the review itself.
Can I build an ADU on my property in Brea?
California law allows ADUs on most lots with a house, including in Brea, 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 Brea?
Apply with the City of Brea's Community Development Department, which reviews ADUs through building plan check without a hearing. 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.