Short answer: Orinda has direct BART service on the Antioch to SFO/Millbrae line, but total commute time depends on the home-to-station trip, wait time, service conditions, destination, and final connection. A fixed estimate can become stale quickly.
Local Context
Test the door-to-door journey on a representative weekday. Include parking or walking, platform time, the San Francisco station you actually need, and the last mile.
What to Verify
Use BART’s official Orinda station page, trip planner, real-time departures, and service advisories. Recheck shortly before making a time-sensitive decision.