Portola Valley, California Zoning Map
Zoning, overlays and hazards on every parcel — and an answer to what the code actually lets you build. Compiled from current zoning data for all 16 districts.
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What's in the Portola Valley dataset
Every field below is available for any Portola Valley parcel, on the map and through the AI.
Zoning
- District code & full name
- Parcel boundary & APN
- All 16 districts mapped
Building controls
- Maximum building height
- Floor area ratio (FAR)
- Front setback
- Side setback
Overlays, hazards & AI
- Flood hazard & environmental layers
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Where uses are permitted in Portola Valley
Share of Portola Valley's zoned land where each use is permitted.
- Single-family
- 99.83%
- Multi-family
- 99.83%
- Retail
- 55.45%
- Eating & drinking
- 0.17%
- Office
- 0.19%
- Storage & warehouses
- 1.00%
Portola Valley, California Zoning Districts: What Do They Mean?
Zoning districts are areas regulated by specific laws that determine land use, building types, and development rules. Each district below shows its zone type and which uses it permits.
| Zone Code | Category | Area | Details |
|---|---|---|---|
A-P Administrative Professional District | - | 11.2 ac | Standards & uses → |
C-C Community Commercial District | - | 9.9 ac | Standards & uses → |
M-R/7.5A/SD-3/DR Mountainous Residential 7.5 Acres Slope Density And Design Review Combining District | - | 1,983.9 ac | Standards & uses → |
OA(R-E/1A/SD-1) Open Area And Residential Estate 1 Acre Slope Density District | - | 17.2 ac | Standards & uses → |
Showing 4 of 16 districts
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Each one runs against the live Portola Valley dataset and returns the districts, standards and approvals involved.
What should developers know about Portola Valley zoning?
Portola Valley is a hillside residential enclave on the San Francisco Peninsula with 16 zoning districts, nearly all of them large-lot residential estate categories that incorporate slope density formulas. The single largest designation is M-R/7.5A/SD-3/DR (Mountainous Residential, 7.5-acre minimum, with slope density and design review) at 1,983.93 acres - the dominant land use in the town. Adding R-E/1A/SD-1A (Residential Estate, 1-acre slope density, 1,071.89 acres), R-E/2.5/SD-2.5 (756.54 acres), R-E/3.5A/SD-2/D-R (955.22 acres), and the Planned Community zone (PC/2A/SD-1 at 454.1 acres), the vast majority of Portola Valley's acreage carries minimum lot sizes of 1 acre or larger, with density further constrained by site-specific slope calculations.
Commercial and professional uses are nearly absent at scale: the Community Commercial District (C-C) covers just 9.92 acres and the Administrative Professional District (A-P) 11.23 acres. Combined, these two zones total fewer than 22 acres in a jurisdiction of several thousand acres - signaling that Portola Valley is intentionally non-commercial and that residential single-family development is the only realistic development typology for the bulk of the land base. Design review overlay (D-R suffix) appears on multiple estate zones, meaning architectural review requirements apply broadly.
For buyers and investors, Portola Valley is characterized by high land values, strict environmental and slope constraints, and minimal pathways to density increases. SB-9 lots splits and ADUs remain theoretically available under California law on qualifying single-family parcels, but the large-lot, hillside terrain of most parcels limits practical ADU feasibility. Building controls include FAR, density, lot, coverage, setbacks, and height across all districts. This is pre-development intelligence, not legal advice - verify with the local planning department before acquisition.
Portola Valley zoning: frequently asked questions
What is slope density zoning and how does it apply throughout Portola Valley?
Most of Portola Valley's residential zones incorporate a slope density formula - meaning that as the steepness of a parcel increases, the allowable density decreases, often below the nominal minimum lot size stated in the zone code. Zones like M-R/7.5A/SD-3/DR and R-E/2.5/SD-2.5 impose this constraint across thousands of acres, so a parcel's actual buildable yield must be calculated from slope data, not just the acreage. Due diligence requires a topographic and geotechnical review before any acquisition.
Can multifamily or ADU development occur in Portola Valley?
Multifamily development is not a viable path under current zoning - there are no multifamily residential districts, and the commercial zones are too small for housing overlays. However, California ADU law requires ministerial ADU permits on qualified single-family lots regardless of local zoning, so existing large-lot homeowners can add attached or detached accessory units. The practical constraint is that terrain, setback requirements, and septic/sewer infrastructure on hillside lots often limit where ADUs can physically be placed.
What does the Design Review (D-R) combining district mean for project entitlement?
Multiple Portola Valley estate zones carry a D-R (Design Review) combining designation, including M-R/7.5A/SD-3/DR, R-E/2A/SD-1/D-R, R-E/2A/SD-2/D-R, and R-E/3.5A/SD-2/D-R. Design review requires architectural and site plan approval from the town's Architectural and Site Control Commission in addition to standard permits - evaluating factors like visual impact from public areas, grading, vegetation removal, and compatibility with the rural character of surrounding properties.
How does the Planned Community (PC/2A/SD-1) zone differ from standard estate zoning?
PC/2A/SD-1 covers 454.1 acres and was established for master-planned residential communities where a unified development plan governs the site rather than parcel-by-parcel standards. Within a Planned Community designation, development rights and standards may differ from the base zone minimum - the applicable master plan document controls. Buyers of PC-zoned parcels should obtain the governing CC&Rs and development plan to understand what can be built, modified, or subdivided.
Is there any commercial investment opportunity in Portola Valley?
Commercial real estate in Portola Valley is extremely limited - C-C (Community Commercial) covers only 9.92 acres and A-P (Administrative Professional) 11.23 acres, totaling under 22 acres. These zones serve neighborhood-scale retail and professional offices for residents rather than regional commercial activity. The constrained supply makes existing commercial properties valuable as income assets, but there is little room for new commercial development or repositioning.
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Zoning data is pre-development intelligence, not legal advice. Verify with the Portola Valley planning department before acquisition or design.