What is Downey's housing like?
Downey became the 50th incorporated city in Los Angeles County on December 17, 1956. The city says that at incorporation it held some of the finest new homes in southeastern Los Angeles County, and that its land grant lay between the Rio Hondo and the San Gabriel River. Today it covers 12.41 square miles with more than 113,000 residents.
Its growth was tied to aviation: Vultee Aircraft was the biggest employer during World War II, and North American Aviation's Downey facilities later became the birthplace of Apollo program systems.
Does Downey have pre-approved ADU plans?
Yes, for detached ADUs. As of October 2026, the city's pre-approved standard plan program works like this:
- Get Planning pre-approval by submitting a site plan.
- Choose a pre-approved ADU from the city's website.
- Work with that plan's designer to adapt it to your lot. The city notes the plans are only about 80% complete and always need property-specific changes.
- Submit a permit application and pay a site-specific review fee, billed as one hour for Building, Planning, Fire and Engineering review.
- Departments review at the same time; the Building Division approves once all sign off.
The designer keeps the copyright, so you contract with the designer directly. We can coordinate that, or design a custom unit if no pre-approved plan fits.
How do I submit ADU plans in Downey?
Electronically. As of October 2026, Downey requires all plans to be submitted through its online Citizen Access (ACA) portal. A New Address Request is filed at plan submittal for the new unit.
What does the Downey Fire Department review?
The city's ADU Fire Plan Guide covers fire access, fire sprinklers and hydrants, egress and emergency escape, and smoke alarms. If sprinklers are required, they may be a deferred submittal, but framing cannot be approved until they are.
Which rules apply to Downey ADUs?
Downey's ADU standards are in Downey Municipal Code Section 9414, which must follow state law. As of October 2026, state law means, for example, 4-foot side and rear setbacks for new detached units, no replacement parking for a garage conversion, and no impact fees on ADUs of 750 sq ft or less.
Pre-approved plan or custom design?
It depends on your lot. A pre-approved plan can speed up review if it fits your yard with little change. A lot with an odd shape, a pool, a large tree or a garage you want to keep may need a custom layout. We compare both before you commit.
Related
As of October 2026. Sources: City of Downey city profile, ADU information page and pre-approved ADU plans page; California Government Code.
See what fits on your Downey lot
Send your address. We check whether a pre-approved plan fits your yard.