Downey · ADU permits
ADU permits in Downey
How to build a ADU in Downey: permit pathway through Downey Community Development Department, drawings required, local watch-outs, and a free address-level wizard for your Downey lot.
Downey context
Downey's ADU ordinance is in Downey Municipal Code Title 9. The city aligns with the California state baseline. Plan check is typically 45-60 days.
- Permit agency
- Downey Community Development Department
- Median lot size
- 6,500 sqft
- ADU permits issued (2025)
- 468Source: Cal HCD Annual Progress Report 2025 (Table A2, BP_ISSUE_DT1 set)
Downey ADU ordinance
Verified against Downey Community Development Department's published ordinance on 2026-05-12. State law (CA Government Code §65852.2) overrides any locally-stricter rule.
Max detached ADU size
1,200 sqft (state default)
Max ADU height
16 ft / 18 ft with second-story setbacks
Setbacks
4 ft side / 4 ft rear (state minimum)
Local processing time
45-60 days for standard ADUs
Pre-approved standard plans
None city-specific
Drawings you'll need to submit
Type your address. See if you can build an ADU, what kind, and exactly how to permit it.
- Site plan (parcel layout + setbacks)
- Proposed floor plan
- Elevations (each side)
- Title 24 CF1R energy compliance
PermitPathLA generates the site plan free from your Downey address. The other drawings come from your architect or plan firm — we list pre-approved options in the wizard.
Downey watch-outs for ADU
Local quirks
Downey Unified school fees apply
Downey Unified School District (DUSD) charges school facility fees on ADUs over 500 sqft.
Apollo site (now Columbia Memorial Space Center) is a real local landmark
If you're marketing a future ADU rental, the Apollo program history and the Columbia Memorial Space Center are major local identity anchors that draw families.
Run your Downey address through the wizard
We pull your parcel polygon from county GIS, apply Downey ordinance + state baseline rules, generate the site plan, and walk you through the Downey Community Development Department submittal. Free, no signup.