Contra Costa County · California
Orinda ADU guide: local rules, permits & property planning
Orinda separates streamlined and standard ADU categories, while Contra Costa County supplies building-permit services. The conversion or new-construction choice affects both the zoning discussion and the documents to prepare.
Local planning guide · Reviewed October 2, 2026
What matters for an ADU in Orinda
Permitting authority: City of Orinda — ADUs
Official local guidanceLocal rules and design checks
| Topic | Local guidance |
|---|---|
| Existing-space conversions | The City distinguishes conversions within existing living or accessory space from newly built ADUs. |
| Side and rear yards | Orinda’s published guidance identifies four-foot setbacks for new units, with different treatment for qualifying existing-space conversions. |
| Parking | Its guidance distinguishes streamlined units from standard units and lists transit and conversion exceptions. |
Selected local requirements, not a complete zoning determination. Confirm the current rules for your address with the responsible agency.
Fees and budget checks
Obtain Orinda’s planning assessment and the County’s separate building assessment. Identify the serving sanitary and fire agencies using the County directory; a City planning payment does not settle every agency charge.
Contra Costa County ADU permitting and agency resourcesHow to start the permit process
Confirm the current City ADU category and zoning requirements, obtain Orinda planning approval, then submit the building package through County ePermits. Reconcile older City summaries with current state requirements during planning review.
Municipal design guidance
Orinda’s conversion versus new-build comparison
The City’s guide distinguishes existing-space and detached-new-construction paths. Use that comparison to organize the scope, not as a parcel-specific approval.
View the original sourceOrinda ADU questions
- Do I apply only to the County?
- No. County guidance requires Orinda planning approval before the building application.
- Does converting a garage have the same parking treatment as a new ADU?
- Orinda lists conversion-related parking exceptions. Identify the existing permitted use and the proposed scope with Planning.
Sources for this guide
- City of Orinda — ADUs
- Contra Costa County ADU permitting and agency resources
- County city and agency directory
Local sources reviewed October 2, 2026. Historical examples retain their stated dates. Contact ADU California to confirm project availability; this guide does not establish an office location or property approval.
A useful first review
Separate what is available from what still needs verification.
01
Confirm the property
Start with a complete address and review the available parcel, building, and map context.
02
Identify the unknowns
Keep missing setbacks, easements, utilities, access, hazards, and local requirements visible.
03
Choose the next review
Use the preliminary result to prepare a focused conversation with the required professionals and agencies.
Explore project types
Compare the scope before choosing a solution.
These pages explain the questions each project type introduces. They do not assert that a particular scope is permitted or suitable for your address.
Compare planning footprints
See common ADU sizes before choosing a design.
These model pages are planning references only. They are not a statement that a particular size is allowed or buildable at a Orinda address.
California directory
Explore more city guides.
The next useful action
Put your address at the center of the conversation.
The online review is preliminary and is not a permit decision, survey, engineering opinion, construction document, final price, or guaranteed schedule.