San Carlos, California Zoning Map

San Carlos has created a layered mixed-use framework with district codes spanning the downtown core (MU-DC-100 at 33 acres), downtown (MU-D-120 at 20 acres), neighborhood corridors, north and south boulevard, and a dedicated station area (MU-SA). These districts are designed to concentrate residential and commercial activity along the Caltrain corridor, and they carry separate height and density controls encoded in the district names. Projects in these zones are typically the strongest candidates for density bonus incentives under California law.

Dedicated multifamily zones include RM-100 (Multiple Family Residential, 59 acres), RM-20 (Multi Family Low Density, 140 acres), and RM-59 (Multi Family Medium Density, 7 acres), together providing about 206 acres. The RS-3 (Single Family Low Density) district at 149 acres and the dominant RS-6 (Single Family Residential) at 1,800 acres are eligible for ADUs by right under California state law, and SB-9 applies to single-family parcels for lot splits and duplexes.

San Carlos has a substantial industrial footprint along the Bay: Heavy Industrial (IH) at 149 acres, Light Industrial (IL) at 95 acres, General Commercial Industrial (GCI) at 72 acres, Industrial Arts (IA) at 28 acres, and Industrial Professional (IP) at 25 acres - over 370 acres total. These properties attract life science, flex-R&D, and traditional industrial tenants seeking Peninsula access with Bay frontage. Some of these sites have been subject to life science conversion interest given the broader Caltrain corridor's biotech demand.

The Airport (A) zone at 85 acres covers San Carlos Airport (SQL) and its immediate operational area. Properties near the airport boundary are typically subject to airport land use compatibility constraints set by the San Mateo County Airport Land Use Commission, which can restrict residential densities, establish noise exposure thresholds, and limit certain uses within safety zones. Developers acquiring land near the airport should consult the applicable airport land use compatibility plan before underwriting a project.

Neighborhood Retail (NR) at just 1 acre and the mixed-use district series serve most neighborhood retail demand, while General Commercial Industrial (GCI) accommodates a broader range of commercial and light-industrial uses. The various mixed-use corridors (North Boulevard, South Boulevard, Downtown) typically require or encourage ground-floor retail as part of mixed-use projects. San Carlos lacks a large standalone highway commercial zone, reflecting its more pedestrian-scaled commercial character.