Commercial Real Estate in San Mateo County: Unincorporated Districts, Coastside Rules and City Codes

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

Most commercial property in San Mateo County sits inside its twenty cities and towns, from South San Francisco’s biotech campuses to downtown Redwood City and San Mateo. The County itself zones a smaller but distinct set of business areas: Middlefield Road in North Fair Oaks, the Coastside harbor and Highway 1 villages, unincorporated Colma, Broadmoor, the Harbor Industrial Area near Belmont, and rural towns like Pescadero and La Honda. Confirm whether a parcel is city or County before relying on any rule.

Who controls the parcel

Inside cities and towns, city codes apply. In unincorporated areas, County Planning and Building applies Title 8, the Zoning and Development Code, which took over from the old zoning regulations when the Board reorganized the County Ordinance Code on October 8, 2024. On the coast, the County’s Local Coastal Program adds coastal development rules and a Coastal Development combining district.

Area	Who regulates commercial use	Our guide
South San Francisco, San Bruno, Millbrae, Burlingame, Brisbane	Each city	South San Francisco, San Bruno, Millbrae, Burlingame, Brisbane
San Mateo, Foster City, Belmont, San Carlos, Redwood City	Each city	San Mateo, Foster City, Belmont, San Carlos, Redwood City
Menlo Park, East Palo Alto, Atherton, Woodside, Portola Valley	Each city or town	Menlo Park, East Palo Alto
Daly City, Colma, Pacifica, Half Moon Bay, Hillsborough	Each city or town	Daly City, Colma, Pacifica, Half Moon Bay
Unincorporated bayside (North Fair Oaks, Broadmoor, Emerald Hills, Harbor Industrial Area, West Menlo Park)	County Title 8	Broadmoor, Emerald Hills
Unincorporated coast and south coast (Montara, Moss Beach, El Granada, Princeton, Pescadero, La Honda, San Gregorio, Loma Mar)	County Title 8 and Local Coastal Program	El Granada, Montara, Moss Beach, Pescadero, La Honda

San Mateo County zoning for commercial, industrial and mixed use

Chapter 8.08 lists the County’s districts. Several are tailored to one neighborhood.

District	Intended uses	Notes
O Office (Ch. 8.64)	Offices
C-1 Neighborhood Business (Ch. 8.68)	Neighborhood retail and services	Variants for North Fair Oaks (8.70) and West Menlo Park (8.72)
C-2 General Commercial (Ch. 8.76)	Broader commercial uses	North Fair Oaks variant (8.78)
CMU-1, CMU-3, NMU (North Fair Oaks)	Commercial and neighborhood mixed use	Middlefield Road corridor
CMU-2, NMU-ECR	Mixed use on El Camino Real/5th Avenue
CCR Coastside Commercial Recreation (Ch. 8.82)	Visitor, boater and Coastside resident services	Use permit for most uses
H-1 Limited Highway Frontage (Ch. 8.60)	Highway-oriented uses
EG El Granada (Ch. 8.52)	El Granada gateway area
M-1 Light Industrial (Ch. 8.86)	Light industry	North Fair Oaks (8.88) and Edison Way (8.90) mixed-use industrial variants
M-2 Heavy Industrial (Ch. 8.94)	Heavier industry
W Waterfront (Ch. 8.98)	Waterfront uses
PC Planned Colma; PC-HD Planned Colma High Density (Ch. 8.115)	Unincorporated Colma	PC-HD adopted April 2026
TS-MU Transit-Supportive Mixed-Use (Ch. 8.116)	Mixed use near transit	Adopted April 2026

Combining districts change what a base zone allows: Airport Overlay (AO), Coastal Development (CD), Design Review (DR), Geologic Hazards (GH) and an Entertainment Overlay (E) all appear in Section 8.08.020.

North Fair Oaks, the harbor and the new 2026 districts

North Fair Oaks. The County has separate C-1, C-2, M-1 and mixed-use districts written only for North Fair Oaks, plus an M-1/Edison district for the industrial pocket along Edison Way, whose development standards follow the M-1/NFO chapter. For a Middlefield Road building, the North Fair Oaks variant, not the countywide C-1, is what controls.

Pillar Point and the Coastside. The CCR district is aimed at visitors, boat users and Coastside residents. Marine trades, fish sales, boat repair, restaurants and hotels each need a use permit, most retail and fuel sales are barred in the shoreline area, and bars are barred on the shoreline but possible inland. Height is 36 feet, or 28 feet east of Denniston Creek, lot coverage tops out at 50% and impervious surface at 10%. Apartments are possible only above the first floor and cannot exceed the commercial floor area.

Colma, Broadmoor and the Harbor Industrial Area. On April 21, 2026, the Board adopted three new districts for parts of these communities: Planned Colma High Density, Transit-Supportive Mixed-Use and a multiple-family mixed-density residential district. Owners of older commercial or industrial parcels there should check whether they were rezoned.

Coastside permits and lodging

Coastal permits. Coastside parcels carry the Coastal Development combining district, and many also require review by the Coastside Design Review Committee listed on the County’s Planning page.

Midcoast housing cap. Mixed-use projects with housing on the urban Midcoast face a 40-unit-a-year cap under LCP Policy 1.23; after 102 units were permitted in 2025, the County says only 18 residential permits may be issued across 2026 and 2027, and it will not accept new residential building permit applications until January 1, 2028 or until an LCP amendment providing relief takes effect. A Coastal Commission hearing on amendment LCP-2-SMC-26-0048-1 is set for November 4, 2026; the County does not state the outcome.

Lodging tax. Hotel and short-term rental operators in unincorporated areas register and file transient occupancy tax through the County’s contractor, HdL; the page does not post the rate.

Transfer tax, business tax and property tax

The County Recorder collects documentary transfer tax at recording, and several cities add their own; we did not verify the rates for this page, so confirm them on the escrow estimate. A change of ownership generally triggers Proposition 13 reassessment. We did not verify an unincorporated business license tax.

Due diligence that matters in San Mateo County

Confirm city or County; North Fair Oaks and Broadmoor parcels often carry city mailing addresses.
For County parcels, check whether a neighborhood-specific district applies and every combining district.
On the Coastside, plan for coastal permits, design review and CCR use permits.
Near SFO, Half Moon Bay or San Carlos airports, check the Airport Overlay.
On the urban Midcoast, check the housing cap before underwriting any residential component.
Work through our commercial due diligence checklist.

Questions people ask

Who zones commercial property on Middlefield Road in North Fair Oaks?

The County, using North Fair Oaks versions of the C-1, C-2, M-1 and mixed-use districts.

What can go near Pillar Point Harbor?

CCR land is aimed at visitor and boating uses; marine trades, restaurants and hotels need a use permit, and most retail is barred on the shoreline.

Can I add apartments above a Coastside shop?

In CCR, yes with a use permit, above the first floor and no larger than the commercial space, and subject to the Midcoast housing cap.

What changed in unincorporated Colma and Broadmoor in 2026?

The Board adopted new high-density, transit-supportive mixed-use and mixed-density residential districts on April 21, 2026.

Which code governs unincorporated San Mateo County now?

Title 8, the Zoning and Development Code, adopted in the October 2024 reorganization.

Who collects hotel tax in unincorporated areas?

The County, through its contractor HdL.

Does Diamond handle commercial property in San Mateo County?

Contact Matthew Martinez to discuss buying, selling or leasing commercial property in San Mateo County.

Sources & notes

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

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