The state-mandated heights
California state law (effective 2023 amendments) sets minimum allowable ADU heights that cities cannot reduce:
- Detached ADU on single-family lot: 16 feet single-story; 18 feet if near transit; 25 feet if attached/within ½ mile of transit
- Detached ADU on multifamily lot: 18 feet minimum
- Two-story ADU above existing structure: Allowed if main structure is also two-story
Height measurement
Height is measured from natural grade at the lowest exterior wall to the highest roof point. Hillside lots get measured differently — typically average grade.
City restrictions
Cities cannot impose lower heights than the state minimums above. Some cities allow taller — Los Angeles allows 25 ft in many zones, OC cities typically cap at 18 ft.
Two-story ADU economics
A two-story ADU costs roughly 15–25% more per square foot than single-story but doubles usable space on small lots. For lots under 5,000 sf, two-story often makes more financial sense.
Real city height limits
| City | Single-Story Max | Two-Story Max |
|---|---|---|
| Los Angeles | 16–25 ft | 25 ft |
| Pasadena | 16 ft | 25 ft |
| Anaheim | 16 ft | 18 ft |
| Irvine | 16 ft | 18 ft |
| Long Beach | 16 ft | 25 ft |
Common height challenges
- Tall pitched roofs (gable, hip) can push two-story height over 25 ft
- Mechanical equipment (HVAC condensers) does not count toward height in most cities
- Solar panels do not add to height
Frequently Asked Questions
What is the maximum ADU height in California in 2026?
25 feet for ADUs near transit (½ mile) or attached to two-story homes; 16–18 feet in most other cases.
Can I build a two-story ADU?
Yes — state law explicitly allows two-story ADUs in most jurisdictions.
Do solar panels count toward ADU height?
No — solar PV equipment is excluded from height calculations.
Can my city impose lower heights than state law?
No — state minimums are a floor; cities can only allow taller.
What about ADUs above garages?
Above-garage ADUs are explicitly allowed under state law up to 25 feet.
Related Vision ADU Resources
- ADU Utility Hookups: Water, Sewer, Electric & Gas (California 2026 Guide)
- ADU Rental Income Calculator: Realistic 2026 California Returns by City
- ADU vs Home Addition: Which Adds More Value in California (2026)?
- ADU Insurance Coverage in California (2026 Guide)
- ADU Contractor in Torrance
- ADU Contractor in Anaheim
- Los Angeles County ADU Builder
- Orange County ADU Builder
- Inland Empire ADU Builder
- 2026 ADU Cost Calculator
- All Vision ADU Service Areas