Local zoning · Portola Valley

Portola Valley — Signage

Q: What signs are allowed in Portola Valley without ASCC approval?

Small, enumerated signs listed in § 18.40.030 A–J are permitted across districts — examples include trespass/warning signs, utility safety signs, one construction sign (commercial/institutional) up to 10 sq ft , real estate signs up to 4 sq ft , nameplates up to 1 sq ft , flags, and certain parking designation signs. Larger or non‑listed signs generally require submittal to the ASCC under § 18.40.070 .

Q: Are freestanding signs limited in height?

Yes — freestanding signs cannot exceed 16 feet in height under § 18.40.050.C . Also note that freestanding signs may not be internally illuminated ( § 18.40.050.J ).

Signage under the Portola Valley local zoning and planning code, with the controlling citations.

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Last reviewed: July 2, 2026

Overview

This page explains what the Town of Portola Valley's zoning ordinance (Title 18) actually requires for signs: what types are automatically allowed, size/height and illumination limits, temporary-sign rules, nonconforming sign removal, and when Architectural and Site Control Commission (ASCC) approval is required. For procedural and design-control matters expect discretionary review by the ASCC or Planning Commission; see the town's design review rules for how aesthetic review is applied. All sign work must also meet the state California Building Standards Code when applicable; the ordinance explicitly requires compliance with the building code. Relevant ordinance text lives in Title 18, Chapter 18.40 (Sign Regulations) and associated definitions in Chapter 18.04.

What the code covers (quick map)

Rules that apply to all districts (permitted sign types, temporary signs, illumination, right‑of‑way, maintenance, and general limits) — see § 18.40.030 and § 18.40.050.
Specific rules for commercial/office/agricultural zoning — the C‑C, A‑P, and O‑A districts — in § 18.40.040.
Special provisions for motor fuel pricing signs and the Town’s scenic corridors (Portola Road and Alpine Road) — § 18.40.041.
Definitions (what counts as a “sign” and how area is measured) — § 18.04.430 and § 18.04.440.
Nonconforming sign removal deadlines and enforcement — § 18.40.060 and § 18.40.080.

District-by-district breakdown

All districts (general baseline)

Purpose/where it applies: rules in § 18.40.030 and § 18.40.050 apply townwide unless a district rule overrides them.
Typical permitted signs: trespass/warning signs, highway markers, utility safety signs, public notices, one construction sign per commercial/institutional project (max 10 sq ft) and construction signs for residential projects limited so total signage per residential construction project does not exceed 10 sq ft, real estate signs up to 4 sq ft, nameplates up to 1 sq ft, flags and certain plaques — see the enumerated list in § 18.40.030.
Key dimensional/illumination standards: no freestanding sign taller than 16 ft; no sign attached to a building taller than the peak of the roof; no internally illuminated sign over 1 sq ft; no freestanding sign may be internally illuminated; internal illumination placed perpendicular to a road is restricted; illuminated signs must use minimum intensity and be limited to the facility’s hours of operation. These limits are in § 18.40.050.
Temporary signs: must be located in approved display locations (maximum area = one‑half of allowable permanent sign area), must be dated, and signs remaining longer than two months are violations; temporary nonconforming signs must be removed within two months. See § 18.40.050.F and § 18.40.060.A.
Review/approval: except for the enumerated small/permitted signs in § 18.40.030 A–J, the design and placement of signs must be submitted to the Architectural and Site Control Commission (ASCC) for approval before installation; appeals are to the Board of Adjustment. See § 18.40.070.

Practical note: measurement of sign area follows the ordinance definitions (smallest enclosing geometric figure for wall/awning signs; full face area for freestanding/projecting signs) in § 18.04.440.

C‑C, A‑P, and O‑A districts (commercial, agricultural‑professional, open area)

Purpose/where it applies: specific commercial/office and agricultural/open-area districts listed in § 18.40.040.
Permitted identification signage: each business may have up to two permanent identification signs that direct attention exclusively to that business. Combined sign area is limited to one‑half sq ft of sign area per linear foot of building frontage, up to 24 sq ft maximum for the two signs combined; one additional sign up to 1 sq ft may describe hours. There are allowances for a group sign (shopping center) up to 50% larger than single‑business limits. See § 18.40.040.A–D for formulas and caps.
Interface with residential lots: a sign shall not face the side line of any adjoining lot in any R district when located within 25 ft of that side line. This protects residential neighbors. (§ 18.40.040.E)

Practical note: when you calculate frontage‑based allowances, confirm which elevation is treated as the “building frontage” because area limits are tied to that linear frontage measurement — Verify with the jurisdiction.

Scenic corridor / Motor fuel stations

Portola Road and Alpine Road are treated as scenic corridor areas; the code creates a limited exemption from California Business & Professions Code §13531 for fuel price signs within those corridors, but fuel price area may be excluded from sign‑area limits only within the minimum standards of state law. The Planning Commission may impose conditions on fuel‑selling facilities and the ASCC reviews fuel price signs. See § 18.40.041.

Practical note: fuel price signs are uniquely regulated and often require ASCC review and use‑permit conditions; expect extra restrictions within the scenic corridor. See the Town’s overlay districts rules for any additional corridor controls.

Quick reference standards table

Rule / permitted use	Limit / rule	Code reference
Real estate sign on property for sale	4 sq ft max	§ 18.40.030.G
Construction sign (commercial/institutional)	10 sq ft max; remove on completion	§ 18.40.030.E
Construction signs (residential)	Total signage per project ≤ 10 sq ft	§ 18.40.030.F
Commercial identification (C‑C / A‑P / O‑A)	0.5 sq ft per linear foot frontage; 24 sq ft max combined for two signs	§ 18.40.040.B
Freestanding sign height	16 ft max	§ 18.40.050.C
Signs attached to structure	Cannot exceed the peak of the roof	§ 18.40.050.D
Internally illuminated signs	Max 1 sq ft for any internally illuminated sign; no internally illuminated freestanding signs	§ 18.40.050.I–J
Temporary sign duration	Must be dated; > 2 months is a violation; temporary nonconforming signs removed within 2 months	§ 18.40.050.F, § 18.40.060.A
Right‑of‑way signs	No sign other than temporary directional/warning sign in public ROW without an encroachment permit	§ 18.40.050.G
Review required	All signs except those enumerated in § 18.40.030 A–J must be submitted to ASCC	§ 18.40.070

Checklist (what an applicant must satisfy)

Confirm the sign type is one of the enumerated permitted small types in § 18.40.030 (if so, may avoid ASCC review).
If not enumerated, prepare sign permit/ASCC submittal with scaled drawings showing sign area calculation per § 18.04.440, materials, colors, mounting, exact location, distance to property lines and neighboring R districts (note 25 ft adjacency rule).
Ensure freestanding height ≤ 16 ft, wall signs do not exceed roof peak, internal illumination complies (≤ 1 sq ft, freestanding prohibited).
If placing a sign in the public right‑of‑way, secure an encroachment permit before installation. § 18.40.050.G applies.
Date temporary signs and verify that display location area ≤ one‑half of allowable permanent sign area (or ASCC‑approved location). Remove temporary signs within 2 months.
Confirm compliance with the California Building Standards Code for structural, electrical, and safety requirements as required by § 18.40.050.H.
If proposing fuel price signage or in the scenic corridor (Portola Road/Alpine Road), prepare for ASCC or Planning Commission conditions under § 18.40.041.

Risks & Ambiguities

Issue	Why it matters	What to verify
ASCC discretion on sign aesthetics and temporary display locations	Many sign approvals are discretionary; even permitted‑size signs can be limited by design review principles.	Verify in writing with ASCC staff whether your proposed sign will require design review or a condition. § 18.40.070
How “building frontage” is measured for commercial sign area formulas	The allowed area for business ID signs is frontage‑based; differing frontage definitions change allowed area.	Confirm which facade counts as the frontage with Planning staff when calculating 0.5 sq ft per linear foot. § 18.40.040.B
Illumination definitions (includes “reflectorized”)	The ordinance treats reflectorized signs as “illuminated,” which restricts many reflectorized materials.	Ask ASCC whether proposed materials (reflective vinyl, etc.) are treated as illumination under § 18.40.050.N.
Scenic corridor / fuel price exceptions	Fuel price signage can be excluded from area limits subject to state law minima, but Town can further restrict area or require conditions.	If proposing fuel price signage, coordinate with Planning Commission and ASCC early; see § 18.40.041.
Measurement of sign area for multi‑face or cylindrical signs	Area measurement rules affect allowable sizes.	Use the definition in § 18.04.440 to compute area and confirm with staff.
Encroachment in the public right‑of‑way	Installing signs in ROW without an encroachment permit is prohibited and enforceable.	Obtain an encroachment permit if any portion of sign or its supports would be in the public ROW per § 18.40.050.G.

Plain-English Summary

Portola Valley’s sign rules are intentionally conservative to protect the town’s rural scenic character: small real‑estate and construction signs are permitted, business signs in commercial districts are limited by frontage formulas and caps, freestanding signs cannot be taller than 16 ft, internally illuminated signage is tightly restricted, temporary signs must be dated and removed within two months, and most non‑small signs require ASCC review before installation. Key code references you’ll need are § 18.40.030, § 18.40.040, § 18.40.050, and § 18.40.070.

Source References

Portola Valley Municipal Code, Title 18 — Zoning: sign definitions and measurement rules: § 18.04.430 and § 18.04.440.
Portola Valley Municipal Code, Title 18 — Signs: permitted signs and general rules: § 18.40.030, § 18.40.040, § 18.40.041, § 18.40.050, § 18.40.060, § 18.40.070, § 18.40.080.
Title 18 (Zoning) header / ordinance source: Portola Valley Title 18, library.municode.com (print export).

If you need the exact ordinance text, consult the Town’s Title 18 (Zoning) sign chapter (Chapter 18.40) in the official municipal code or ask Planning staff to identify any recent amendments to sign rules (Verify with the jurisdiction).

Sources

Retrieved passages

CBC § 2 (§ 2) High relevance
Portola Valley Zoning Code (chapter in) High relevance
Portola Valley Zoning Code (§ 4) High relevance
Portola Valley Zoning Code (§ 1) Medium relevance
CBC § 3 (§ 3) Medium relevance
Portola Valley Zoning Code (§ 1) Medium relevance
Portola Valley Zoning Code (§ 1) Medium relevance
Portola Valley Zoning Code (§ 1) Medium relevance

Cited sections

Official Portola Valley code library

Frequently asked questions

What signs are allowed in Portola Valley without ASCC approval?

Small, enumerated signs listed in § 18.40.030 A–J are permitted across districts — examples include trespass/warning signs, utility safety signs, one construction sign (commercial/institutional) up to 10 sq ft, real estate signs up to 4 sq ft, nameplates up to 1 sq ft, flags, and certain parking designation signs. Larger or non‑listed signs generally require submittal to the ASCC under § 18.40.070.

How large can a business sign be in a C‑C, A‑P, or O‑A district?

Business identification signs in those districts are limited to one‑half square foot of sign area per lineal foot of building frontage, with a combined maximum of 24 sq ft for the two allowed permanent signs per business (plus one 1‑sq ft hours sign). See § 18.40.040.B–C for the exact formula and caps.

Are freestanding signs limited in height?

Yes — freestanding signs cannot exceed 16 feet in height under § 18.40.050.C. Also note that freestanding signs may not be internally illuminated (§ 18.40.050.J).

Can I have an internally illuminated sign?

Internally illuminated signs are tightly limited: no internally illuminated sign shall exceed 1 square foot in area, and a freestanding sign may not be internally illuminated. The code also treats reflectorized signs as “illuminated.” See § 18.40.050.I–N.

What are the rules for temporary signs?

Temporary signs must be located in approved display locations (maximum area = one‑half of the allowable permanent sign area), must be dated, and signs remaining longer than two months are a violation. Temporary nonconforming signs must be removed within two months. See § 18.40.050.F and § 18.40.060.A.

Do I need permission to place a sign in the public right‑of‑way?

Yes — except for certain temporary directional or warning signs, no sign may be placed in the public right‑of‑way without first obtaining an encroachment permit. See § 18.40.050.G.

How is sign area measured?

Sign area is measured per the ordinance definitions: for wall/marquee/awning signs use the area of the smallest geometric figure enclosing the message; for freestanding/projecting/banner signs use the entire face area excluding uprights. See § 18.04.440 for the measurement rules.

What happens if my existing sign doesn’t meet the current code?

The code treats existing signs as nonconforming and requires removal or conformance within set periods: temporary nonconforming signs must be removed within two months, and permanent nonconforming signs must be brought into conformance or removed within two years. See § 18.40.060.

Are fuel price signs treated differently?

Yes. Properties abutting Portola Road and Alpine Road (the Town’s scenic corridors) are subject to special rules: the Town exempts those corridors from the state code provision cited, but fuel price area may be excluded from sign‑area limits only within state minimum standards and is subject to ASCC review and Planning Commission conditions under § 18.40.041. Expect discretionary conditions to protect scenic values.

If I disagree with an ASCC decision, can I appeal?

Yes — an aggrieved applicant or interested property owner may appeal an ASCC determination to the Board of Adjustment within the timeframe set by the zoning title (see § 18.40.070 and related appeal procedures in Chapter 18.66).

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