Commercial Real Estate in San Diego County: City Codes, County Zones and Unincorporated Rules

By Matthew Martinez, Founder, CEO & Managing Broker, Diamond Real Estate Group. California DRE #01869679.

Commercial property in San Diego County is spread across 18 incorporated cities, each with its own zoning code, and a large unincorporated area where the County of San Diego is the land use authority for business districts in communities such as Fallbrook, Ramona, Alpine, Lakeside and Spring Valley. Tribal, military, state and federal land sits outside both systems. The first job on any deal is to confirm which agency controls the parcel, then read that agency’s rules.

Who controls the parcel

The County’s budget overview lists 18 incorporated cities and says that outside them the County provides city-type services such as policing, fire protection, road maintenance and building permits. Within the unincorporated area, its land use reach is narrower than the map suggests: the County’s General Plan page says tribal lands, state and federal lands and military installations such as Camp Pendleton are outside County land use authority, leaving it about 772,239 acres, roughly 35% of the unincorporated area. The General Plan update approved in 2011 steers development into village cores.

Boundaries move. San Diego LAFCO handles annexations, special district formations and out-of-agency service requests, so a parcel at a city edge may be in a pending annexation or rely on a district for water or fire service. Near airports, the San Diego County Regional Airport Authority acts as the Airport Land Use Commission, and its compatibility plans cover noise, safety, airspace and overflight disclosure for both city and County land.

Unincorporated San Diego County zoning for commercial and industrial use

County Planning & Development Services applies the County Zoning Ordinance only outside city limits. Its Property Summary Report shows the zoning for an Assessor’s Parcel Number, and the GIS map shows zoning and General Plan data. The County’s zoning ordinance summary describes the use regulations.

Zoning on a County parcel combines a use regulation with separate development regulations for density, lot size, floor area ratio, height and setbacks in Part Four of the ordinance, plus special area regulations in Part Five for airports, flood plains, design review, historic and scenic areas.

Village rules, community plans and rural business

Part Eight of the ordinance adds village regulations for Fallbrook, Ramona, the Alpine Village Core and Camp Lockett, so a storefront in those town centers follows extra form and use standards on top of the base zone. Community planning and sponsor groups, listed on the County’s community groups page from Bonsall and Valley Center to Julian and Borrego Springs, review projects in their areas and advise the County, but they do not make County decisions.

Rural commercial property often depends on onsite systems. The County’s environmental health department says on its septic FAQ that commercial septic tanks and disposal fields are sized from peak daily sewage flow based on use and occupancy, and that it holds jurisdiction over septic work everywhere in the county, including the cities. A change from retail to restaurant use on a septic parcel can require a new design.

County-specific rules: cannabis, lodging tax and coastal areas

Cannabis. The County’s existing facilities list, dated November 7, 2024, names five cannabis businesses authorized in the unincorporated area as nonconforming uses: three in Ramona and one each with El Cajon and Escondido addresses. Buyers should not assume new cannabis uses are available on County land; check the current ordinance with PDS.

Lodging tax. The County’s transient occupancy tax ordinance sets the unincorporated rate at 8% of rent for stays of 30 days or less, with operators registering with the Tax Collector within 30 days of opening and each July. Cities set their own rates.

Coastal and port land. Part Nine of the County ordinance carries Local Coastal Program regulations for unincorporated coastal areas. In the cities, coastal permits come from each city’s LCP or the Coastal Commission, and some waterfront land is under the San Diego Unified Port District, as Coronado’s code notes for its own bayfront.

Transfer tax, business tax and property tax

The County Recorder collects documentary transfer tax at $0.55 per $500 of value, net of existing liens, and collects it for the county and cities without listing city-specific rates. Several city pages above found no separate city tax; confirm the total on the escrow estimate. A change of ownership generally triggers Proposition 13 reassessment, and many newer areas carry Mello-Roos special taxes. Business license tax is a city matter inside cities; we did not verify an unincorporated business license requirement for this page.

Due diligence that matters in San Diego County

• Confirm the jurisdiction by parcel, not mailing address, using the County Property Summary Report or the city’s map.
• For County parcels, read both the use regulation and the development regulations, plus any village or special area rules.
• Check LAFCO for pending annexations and the water, sewer and fire providers.
• Review airport compatibility plans for parcels near any of the region’s airports.
• On septic, confirm the system design matches the intended commercial use.
• Use our commercial due diligence checklist.

Questions people ask

Sources & notes

1. County of San Diego, county overview
2. County of San Diego, General Plan
3. County PDS, Zoning Ordinance
4. County PDS, Zoning Ordinance summary (PDS-444)
5. County PDS, community planning and sponsor groups
6. County DEHQ, septic FAQs
7. County PDS, existing cannabis facilities list
8. County Treasurer-Tax Collector, TOT ordinance
9. San Diego LAFCO
10. San Diego County Regional Airport Authority, land use compatibility
11. San Diego County Recorder, recording and transfer tax

City rules summarized in the table are covered, with sources, on each linked city page. This page is general information, not legal or tax advice. Last reviewed October 2026 by Matthew Martinez.

Related: San Diego County real estate guide · Multifamily property in San Diego County · Commercial real estate services