It depends on your property's zoning. You can look up the zoning of a parcel and find allowed land uses with this map.
Parcels located in the Coastal Zone (denoted by “CC” zoning) will require Coastal Permits which may have additional restrictions to comply with the Coastal Zoning Ordinance.
Every situation is different, so you should begin by consulting Permit Sonoma planning staff. You may request a formal determination from Permit Sonoma on this question. To do so, you should detail the proposed request in writing. A fee may be charged for this review.