Can an ADU or JADU be used as a short-term/vacation rental?

No. Napa and Sonoma County properties with ADUs and JADUs must file a deed restriction agreeing that the unit will not be used for short-term rentals (less than 30 days). This discourages the listing of ADUs on popular websites like Airbnb and VRBO and promotes them as a means to increase housing stock for the diverse needs of county residents.