The major exemption that changes everything
California state law prohibits cities from requiring off-street parking for ADUs in any of these cases:
- The ADU is within half a mile walking distance of public transit.
- The ADU is within a historic district.
- The ADU is part of a permitted accessory structure conversion (garage, shed).
- On-street parking permits are required but not offered to the ADU occupant.
- A car share vehicle is located within one block of the ADU.
- The ADU is one of several units on a single-family lot under SB 9.
In urban Southern California, the half-mile transit rule covers most properties.
When parking may still be required
If none of the exemptions apply, your city can require one off-street parking space per ADU (not more). This is rare in LA, OC, and most of the Inland Empire because transit and bus stop coverage is broad.
Garage conversion parking
When you convert a garage into an ADU, state law also prohibits cities from requiring replacement parking in most cases. You do not have to build a new carport or driveway pad.
How to confirm your exemption
- Pull up your property on Google Maps.
- Find the nearest bus stop, light rail, or commuter rail station.
- Measure walking distance (not straight-line distance) — half a mile is roughly 10 minutes on foot.
- If you're within that radius, you qualify.
Your builder should document this in the permit submittal to lock in the exemption.
Related reading
Frequently asked questions
Do I have to replace my garage parking when I convert? Usually no — state law removes this requirement in most cases.
Can my HOA require parking even if state law exempts me? HOAs can impose additional restrictions, but they cannot override state law on ADU eligibility.
Does the exemption apply to tandem parking? Yes — many cities count tandem parking toward minimum requirements where parking is still required.