Local zoning · Napa County

Napa County — Signage

Signage under the Napa County local zoning and planning code, with the controlling citations.

Last reviewed: July 6, 2026

Overview

This page distills how Napa County’s zoning code regulates signs in the unincorporated areas. Most rules live in Napa County Code, Title 18 (Zoning), Chapter 18.116 — Signs, with added sign standards in a few districts and overlays. The County’s approach is to allow identification and wayfinding, not advertising, and to protect rural character and safety by tightly controlling size, height, lighting, and location. See the broader context in the county’s zoning framework and zoning districts.

Core rule in plain English: signs in unincorporated Napa County are for identification and wayfinding tied to the premises; off‑site advertising is generally prohibited, and sign size, height, placement and lighting are strictly limited to protect safety and rural character (§ 18.116.010; § 18.116.065).

Countywide Sign Regulations (apply in all base districts unless a more specific standard below controls)

Purpose and scope. Chapter 18.116 aims to eliminate excessive/confusing displays, ensure on‑premises identification (not advertising), reduce hazards, and preserve scenic quality in unincorporated areas (§ 18.116.010).
Signs allowed without a permit. Examples include a 1 sq ft occupant nameplate, a 6 sq ft unlighted real‑estate sign while the property is for sale/lease, a 6 sq ft construction sign while work is active, and political signs up to a 128 sq ft aggregate per parcel with timing limits (§ 18.116.020).
Signs allowed with an administrative permit. One on‑site directional sign per business; up to two directional signs in the right‑of‑way with encroachment approval; one 6 sq ft, ≤4 ft‑high, non‑illuminated agricultural business sign per parcel (farms/ranches/vineyards, not wineries); temporary off‑site signs for seasonal ag retail under § 18.116.041; and limited hospital emergency wayfinding (§ 18.116.030). Issuance ties to § 18.116.030 and § 18.116.055 via the administrative permit process in Chapter 18.126 (§ 18.126.060(D)–(E)).
Comprehensive Sign Plans (CSP). Required for multi‑tenant business complexes in commercial zoning districts unless a use permit already sets sign specs; also used for winery identification signs lacking prior approvals; for signs in a specific plan area; and for agricultural association systems (§ 18.116.035). Approval requires design compatibility findings (§ 18.116.036). For projects subject to design review, CSP content typically coordinates with that process.
Directional signs. Tight template: copyboard ≤1 ft high × 3 ft long; height ≤6 ft above roadway centerline; white reflective copy on solid blue background; letters ≤4 in; may be on‑site or in ROW with approvals (§ 18.116.055).
Winery signs. Governed entirely by use permit or CSP; unless permitted for public tours/tastings before Feb. 22, 1990, entrance signage must state “Tours and Tastings by Prior Appointment Only.” Baseline limits: up to 30 sq ft total freestanding; up to 12 sq ft total wall; freestanding height ≤6 ft above natural grade or ≤4 ft above roadway centerline, whichever is greater (§ 18.116.060).
Prohibited signs. Off‑site advertising except narrow allowances; signs above roofs; movable or ground‑sitting signs that aren’t anchored; moving/flashing lights; exposed artificial lighting except as allowed; abandoned/illegible signs; aviation hazards in :AC; freestanding signs >15 ft high or >50 sq ft with any dimension >15 ft (§ 18.116.065).
Absolute height cap and lighting. No sign taller than 12 ft overall unless a more specific section sets a lower limit; illumination only if expressly authorized; neon/internal illumination only in commercial/industrial districts and only via an approved CSP; no spillover to neighbors (§ 18.116.070; § 18.116.075).
Maintenance, enforcement, and nonconforming signs. Owners must maintain signs; penalties apply for installing permit‑required signs without approvals; permits can be revoked; nonconforming signs follow abatement timelines and removal/storage rules (§ 18.116.080; § 18.116.081; § 18.116.085; § 18.116.090–.110).
Exempt signs. Governmental signs; permitted transit bench ads; certain indoor/not-visible‑from‑property‑edge signs; historic plaques; religious/holiday symbols; “for sale/rent/lease” signs (subject to § 18.116.020(B)); and limited temporary event/promotional devices once per year for up to 30 days (§ 18.116.120).

Sign terms you will see: “sign,” “sign area,” “awning,” “freestanding,” “monument,” “wall,” and “window” signs are defined in § 18.08.560–.579. These definitions matter when sizing and placing a proposal.

For structural and electrical safety, separate state rules apply under the California Building Standards Code; the County’s zoning sign limits do not replace those state requirements.

District-by-District Standards and Overlays (unincorporated areas)

Airport Industrial Area (AIASP)

Purpose. Implements the Airport Industrial Area Specific Plan with coordinated, low‑profile monument and building identification signs tailored to business parks (§ 18.116.045).
Typical permitted sign types. Site identification (one per site/per street frontage); building identification (one monument + one wall per building; tenant listings possible on monument); standardized tenant door signs; limited directional and permanent informational signs (§ 18.116.045(B)).
Key dimensional standards. Monument signs oriented perpendicular to street and at least 5 ft from ROW; building wall signs ≤3% of wall area; monument building ID ≤4 ft high and ≤32 sq ft; permanent informational ≤6 sq ft and ≤12 ft high (§ 18.116.045(B)).
Lighting/materials. External lighting allowed for site/building ID; tenant/directional signs unlit; durable materials; no temporary/movable signs (§ 18.116.045(C)–(D)).
Where it applies. Parcels within the adopted AIASP boundaries; where a specific plan is stricter, the plan controls (§ 18.116.045(A)). Coordinate with overlay districts as applicable.

Napa Pipe districts — MUR, IBP, IBP‑W

Purpose. Mixed‑use and industrial/business park districts with project‑specific design guidelines that also govern signage (§ 18.66.310).
Typical permitted sign types. Building identification consistent with adopted development plan/design guidelines; signs otherwise follow CSP and countywide rules (§ 18.66.310(A)–(B); § 18.116.035–.036).
Key dimensional/lighting points. One monument and one wall‑mounted building identification sign per building in MUR; signs in IBP/IBP‑W must comply with CSP procedures; lighting cannot create aviation hazards and must follow the project’s approved guidelines (§ 18.66.310(A)–(C)).
Where it applies. Properties zoned MUR, IBP, or IBP‑W within the Napa Pipe planning area; confirm with the adopted plan and guidelines through design review.

General Industrial (GI)

Purpose. Industrial areas with signs required to match Chapter 18.116 and be compatible with surroundings (§ 18.44.120(A)).
Typical permitted sign types. Those allowed by Chapter 18.116; if a GI lot is adjacent to or across from an IP‑zoned lot, the GI lot must follow IP sign standards (§ 18.44.120(B)). IP‑specific standards were not in the retrieved materials. Not found in retrieved materials.
Key constraints. Only traffic/street ID signs allowed within public right‑of‑way; lighting designed to avoid off‑site glare/aviation hazards (§ 18.44.120(C), (E)–(F)).
Where it applies. Parcels zoned GI in unincorporated areas; coordinate with development standards for yard/ROW setbacks that affect sign placement.

Airport Compatibility overlay (:AC)

Purpose. Protect aviation safety. Within :AC, any sign that causes an aviation nuisance/hazard is prohibited (§ 18.116.065(N)).
Practical effect. Expect stricter lighting controls; in Napa Pipe districts, illumination is further limited to avoid glare/mimicry of airport lights (§ 18.66.310(C)). Coordinate early with overlay districts.

Countywide baseline (all other base districts)

Purpose. Rural and residential/agricultural areas emphasize minimal, on‑premise identification and wayfinding per Chapter 18.116; off‑site advertising is broadly prohibited (§ 18.116.065(A)).
Typical permitted sign types. Small occupant nameplates, temporary real‑estate/construction, limited agricultural identification and contact signs, and directional signs (many need an administrative permit) (§ 18.116.020; § 18.116.030; § 18.116.055).
Key dimensional standards. Frequent ≤4–6 ft height caps; small areas (often ≤6 sq ft); directional signs fixed blue/white palette and ≤1×3 ft board (§ 18.116.020–.030; § 18.116.055).
Where it applies. All unincorporated parcels outside AIASP, Napa Pipe districts, or other specific plans/overlays.

Use-Specific Countywide Sign Systems

Agricultural association signs. One‑association‑only; 1‑face ≤6 sq ft; height ≤4 ft above road crown (≤6 ft allowed only when one sign identifies multiple eligible properties); spacing from public‑road‑readable signs; no illumination; uniform design; director may exempt for unique site conditions (§ 18.116.040(B)–(C)).
AVA boundary signs. Elliptical aluminum 28 in × 54 in; Burgundy PMS 1955C background; reflective white/cream copy; max height 4 ft above road crown; up to 4 per AVA; spacing/placement rules; no illumination; encroachment permits if in ROW (§ 18.116.043).
Temporary off‑site signs for seasonal ag retail. Within 1/2‑mile radius of key intersection and on designated highways/roads; display ≤45 days/year (extendable once); max two large signs (≤32 sq ft/face) and eight directional signs (≤4 sq ft/face); overall height ≤6 ft (§ 18.116.041).

Common Napa County Sign Limits (unincorporated areas)

Sign type	Allowed?	Max area / face	Max height	Key notes	Code Reference
Occupant nameplate	By right	1 sq ft	Wall‑mounted	Parallel to front wall	§ 18.116.020(A)
Real‑estate (temp)	By right	6 sq ft	—	While offered for sale/lease; unlighted	§ 18.116.020(B)
Construction (temp)	By right	6 sq ft	—	While permitted work is active	§ 18.116.020(C)
Political	By right	128 sq ft aggregate/parcel	—	90 days pre‑election; remove within 10 days	§ 18.116.020(D)
Agricultural business ID (not winery)	Admin. permit	6 sq ft	4 ft	One per parcel; non‑illuminated	§ 18.116.030(C)
Directional (on‑ or off‑site)	Admin. permit	3 sq ft (1 ft × 3 ft board)	6 ft	Blue background; white reflective copy; letters ≤4 in	§ 18.116.055; § 18.116.030(A),(B)
Ag contact sign	By right	3 sq ft	6 ft	Standardized blue/white format; limited content	§ 18.116.020(G)
Seasonal ag retail (temp off‑site)	Admin. permit	Large: 32 sq ft; Dir.: 4 sq ft	6 ft	Max 2 large + 8 directional; roads limited; 45 days	§ 18.116.041(B)
AVA boundary	Admin. permit/CSP	Fixed template	4 ft over road crown	Burgundy PMS 1955C; up to four per AVA; no illumination	§ 18.116.043(B)–(C)
Winery signs	Use permit/CSP	Freestanding: 30 sq ft (total); Wall: 12 sq ft (total)	6 ft over grade or 4 ft over centerline	“Tours and Tastings by Prior Appointment Only” unless grandfathered	§ 18.116.060(B)–(C)
AIASP monument building ID	Use permit/CSP	32 sq ft	4 ft	Near primary pedestrian entry; consistent materials	§ 18.116.045(B)(2)(c)
Absolute countywide cap	—	—	12 ft	Unless a more specific section is lower	§ 18.116.070

Practical notes that matter

Setbacks and rights‑of‑way. Many signs must be outside required road and yard setbacks, and off‑premise/ROW installations need encroachment approval. Coordinate early with development standards and circulation/parking layouts (§ 18.116.030(B); § 18.116.043(B)(2)).
Design coordination. Multi‑tenant, winery, and plan‑area signs typically go through a CSP in tandem with project design review (§ 18.116.035–.036).
Landscaping. Monument signs in AIASP must sit within landscaped setbacks/medians; cross‑check with landscaping and screening standards (§ 18.116.045(B)(1)(b)).
Variations/exceptions. The director may allow limited exemptions for spacing/setbacks for agricultural association and AVA systems due to topography/parcel size; broader relief may require pursuing variances and exceptions (§ 18.116.040(B)(2)(e); § 18.116.043(B)(3)(c)).
Historic contexts. If a parcel also falls under County historic preservation rules or similar conditions, coordinate with historic preservation. Not found in retrieved materials.

Checklist

Identify your zoning and any overlays (e.g., :AC) for the parcel in unincorporated Napa County.
Determine if your sign is by‑right (§ 18.116.020), needs an administrative permit (§ 18.116.030), or must be in a CSP/use permit (§ 18.116.035; § 18.116.060).
Verify size, height, colors, copy, and location against the specific standard (e.g., § 18.116.055 for directional; § 18.116.041 for seasonal ag retail; § 18.116.045 for AIASP).
Confirm setbacks and right‑of‑way status; obtain encroachment permissions if placing in public ROW (§ 18.116.030(B); § 18.116.043(B)(2)).
Check lighting limits; internal/neon lighting generally requires a CSP and is limited to commercial/industrial districts (§ 18.116.075).
For wineries, match your use permit or CSP; include “Tours and Tastings by Prior Appointment Only” if required (§ 18.116.060(B)).
Coordinate monument sign placement with site landscaping and pedestrian entries where required (§ 18.116.045(B)).
Maintain your signs and keep copies of approvals; penalties apply for installing without required permits (§ 18.116.081).

Risks & Ambiguities

Issue	Why it matters	What to verify
12 ft countywide max vs. lower section caps	Specific sections (e.g., directional, monuments) impose lower heights; exceeding a lower cap is a violation	Identify the controlling section for your sign type (§ 18.116.070; type‑specific sections)
Off‑site advertising	Broadly prohibited, with narrow exceptions	Your copy is identification/wayfinding only (§ 18.116.065(A))
ROW placement	Many sign types need to be outside setbacks; ROW installs require encroachment approvals	Whether the installation is in ROW and any County/Caltrans permits (§ 18.116.030(B); § 18.116.043(B)(2))
Winery wording requirement	Missing required “By Prior Appointment Only” phrase can trigger corrections	Your winery’s entitlement date and permit conditions (§ 18.116.060(B))
AIASP vs. base code	Specific plan rules can be more restrictive	Which plan governs your parcel (§ 18.116.045(A))
Napa Pipe design guidelines	Signs must match adopted project guidelines	The approved development plan/design guidelines for your building (§ 18.66.310)
Aviation hazards in :AC	Lighting/glare can be prohibited	Overlay mapping and lighting specs (§ 18.116.065(N); § 18.66.310(C))
IP standards near GI	GI lots by IP must meet IP’s sign standards	The IP sign standards for the adjacent area (§ 18.44.120(B)) — Not found in retrieved materials

Plain-English Summary

In unincorporated Napa County, think small, simple, and on‑premise. Most identification signs are tiny and low, many wayfinding signs use a blue‑and‑white template, and almost all illumination is limited or requires a plan. Special areas like the Airport Industrial Area and Napa Pipe have their own coordinated monument/wall sign systems, while wineries rely on their use permits or comprehensive sign plans.

Source References

Napa County Code, Title 18, Zoning — Signs: § 18.116.010–.120 (purpose; by‑right and permitted signs; CSP; directional; winery; prohibited; height; lighting; maintenance; enforcement; exemptions).
Napa County Code — Temporary off‑site seasonal agricultural retail signs: § 18.116.041.
Napa County Code — AVA and agricultural association signs: § 18.116.043; § 18.116.040.
Napa County Code — Airport Industrial Area sign standards: § 18.116.045.
Napa County Code — Napa Pipe districts signage: § 18.66.310.
Napa County Code — GI district signage cross‑reference: § 18.44.120.
Napa County Code — Definitions of signs: § 18.08.560–.579.

Sources

Retrieved passages

Napa County Zoning Code (§ 1) High relevance
Napa County Zoning Code (§ 1) High relevance
Napa County Zoning Code (§ 2) High relevance
Napa County Zoning Code (§ 1) High relevance
Napa County Zoning Code (Section 18.116.055) High relevance
Napa County Zoning Code (§ 1) High relevance
Napa County Zoning Code (§ 1) High relevance
Napa County Zoning Code (Section 18.116.075) High relevance
Napa County Zoning Code (§ 8) High relevance
Napa County Zoning Code (§ 1) High relevance
Napa County Zoning Code (§ 1) High relevance
Napa County Zoning Code (§ 1) High relevance

Cited sections

Official Napa County code library

Frequently asked questions

Are off-site business advertising signs allowed in unincorporated Napa County?

Generally no. Off‑site advertising is prohibited except for narrow cases like certain directional, seasonal agricultural retail, agricultural association, AVA, and emergency hospital wayfinding signs approved under specific sections (§ 18.116.030; § 18.116.041; § 18.116.040; § 18.116.043; § 18.116.065(A)).

How big can a winery sign be in unincorporated Napa County?

Unless a use permit/CSP sets different limits, wineries get up to 30 sq ft total for freestanding signs and up to 12 sq ft total for wall signs, with freestanding height capped at 6 ft above grade or 4 ft above the road centerline, whichever is greater (§ 18.116.060(C)).

Do I need a comprehensive sign plan for a multi-tenant commercial site?

Yes, multi‑tenant business complexes in commercial districts typically require a CSP, unless a use permit already specifies compliant sign standards. CSP approval hinges on design compatibility findings (§ 18.116.035–.036).

What are the standard rules for directional signs?

Directional signs follow a strict template: board ≤1 ft tall × 3 ft long, height ≤6 ft over roadway centerline, blue background with white reflective copy, letters ≤4 inches, and may be in the ROW with encroachment approval (§ 18.116.055; § 18.116.030(A),(B)).

Are illuminated or neon signs allowed?

Only if expressly authorized. Neon/internal illumination is prohibited unless in commercial/industrial districts and approved within a CSP; in :AC and Napa Pipe districts, extra aviation‑safety limits apply (§ 18.116.075; § 18.116.065(N); § 18.66.310(C)).

What happens if I install a permit-required sign without approval?

The County may impose an administrative penalty and withhold permits until both the fee and penalty are paid. Continued noncompliance can trigger abatement and cost recovery (§ 18.116.081).

Can I place a sign within the public right-of-way?

Only certain types (e.g., directional, AVA) and only with specific encroachment approval from the County or Caltrans, and in conformance with Road and Street Standards (§ 18.116.030(B); § 18.116.043(B)(2)).

Do AIASP properties use different sign rules?

Yes. AIASP requires low monument and building identification signs with strict placement, size, and lighting/material standards; no temporary/movable signs are allowed (§ 18.116.045).

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