It depends. Short-Term Rentals (STRs) are only allowed in the Mountain and Desert regions, and are not allowed in multi-family structures. Additionally, state law requires the rental of certain type of ADUs be for a term longer than 30 days. This restriction prohibits the County from approving an ADU for STR use regardless of its location within the County. ADUs prohibited by the state from being used as a STR are classified by the County as a “by-right” ADU. A by-right ADU is one that the County was required to approve notwithstanding any other applicable County development standard. Your ADU is likely a by-right ADU if “but for” applicable development standards, the County was required to approve a building permit for an ADU because it complied with the following requirements: (A) The ADU is located within the proposed space of a single-family dwelling or existing space of a single-family dwelling or accessory structure, which may include an expansion of not more than 150 square feet beyond the same physical dimensions as the existing accessory structure to accommodating ingress and egress, the space has exterior access from the proposed or existing single-family dwelling, and the side and rear setbacks were sufficient for fire and safety notwithstanding setback restrictions.. (B) A detached, new construction, ADU that does not exceed four-foot side and rear yard setbacks, has a total floor area limitation of not more than 800 square feet, and a height limitation of 16 feet.