In short
- 910 ADU permits on record, nearly all since 2021.
- 211 in 2025, down 10% from 2024.
- Typical permit time: 172 days from application to permit (median of 33 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).
- Lancaster's state reports include almost no ADU permits before 2020 (a few carried in by later reports); 2018 and 2019 counts are incomplete.
Permits by year
Permits by year and type (table)
| Year | All ADU permits | Garage conversions | Detached |
|---|---|---|---|
| 2020 | 12 | — | — |
| 2021 | 122 | — | — |
| 2022 | 159 | — | — |
| 2023 | 172 | — | — |
| 2024 | 234 | — | — |
| 2025 | 211 | 0 | 0 |
“—” means the source for that year does not report ADU type.
Read more: ADU types explained
Not counted above: 156 approved projects with no building permit reported yet.
ADU rules in Lancaster
State law check: No HCD review letter on file (that isn't a finding either way). Its owner-occupancy rule for ADUs and its one-ADU limit are stricter than current state law.
| Rule | Lancaster's code | State law guarantees |
|---|---|---|
| Maximum size | Attached: 850 sq ft (studio or 1 bedroom) or 1,200 sq ft (2+ bedrooms). Detached: no size cap stated, within the zone's lot coverage (40% to 60%). Junior ADU per state law. | 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: 18 ft, plus 2 ft to match the house's roof pitch. Attached: 25 ft. 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 | 4 ft side and rear; 25 ft front for new ADUs; conversions only need fire-safety setbacks. | No more than 4 ft side and rear; none for conversions of existing space. |
| Parking | 1 space unless exempt (conversions, within ½ mile of transit, state-exempt ADUs); a junior ADU in a garage must replace the lost spaces. | 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 | An owner must live on the property, except for ADUs permitted in 2020–2024 without a junior ADU. Deed restriction required. | 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 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 | Not for less 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. |
- Lots on septic systems need a recent percolation test with the ADU application.
- The city sells five pre-approved ADU plans (by RRM Design Group) through its permit portal.
Where local rules conflict with state law, state law controls. Sources: Lancaster Municipal Code §§ 17.41.010–17.41.020 (Ord. 1106, 2023; Ord. 1130, May 27, 2025); HCD's list of review letters; California ADU rules. Verified Sep 30, 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 |
|---|---|---|---|
| Junior ADU (JADU) | not reported | ||
| Unclassified | 172 | 74 – 259 | 33 |
Middle half: the range covering the middle 50% of permits (a quarter were lower, a quarter higher).
Read more: How long ADU permits take in Los Angeles (and other cities) · How long ADUs take to build
From permit to completion
Of the 362 ADU permits Lancaster reported issuing from 2020 through 2023, 203 (56%) have a completion reported to the state. For those, the median time from permit to completion was 14 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 Lancaster? Feature your business on this page.
Questions about ADUs in Lancaster
How many ADUs have been permitted in Lancaster?
Public records show 910 ADU permits in Lancaster through 2025, nearly all since 2021. 211 in 2025, down 10% 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 Lancaster?
Among the 33 ADU permits in Lancaster with both dates recorded, half were issued within 172 days of the application; the middle half took 74 to 259 days. That includes plan-check corrections and resubmittals, not just the review itself.
Can I build an ADU on my property in Lancaster?
California law allows ADUs on most lots with a house, including in Lancaster, 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 Lancaster?
Apply with the City of Lancaster's Building & Safety Division through the Accela Citizen Access portal, where the city's pre-approved ADU plans are also sold. 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.