The ability to subdivide property depends on a number of things. The first criteria is always the minimum parcel size or density established by the General Plan and zoning map. If you are zoned for 5-acre parcels, that means you must have acreage equal to 5 acres per dwelling unit. If the "density" can be satisfied, the answer is then "maybe." The proposed land division must be able to satisfy requirements for sewage disposal and water supply, and adequate access. The subdivision must also be designed to avoid environmentally sensitive resources as defined by County Zoning Ordinance.
The County Tentative Map Guidelines (PDF) provide detailed information on the procedures that are required before land can be subdivided. To discuss specific issues or concerns about your property you should make an appointment with a County Planner 530-265-1222.