Local zoning · Suisun City

Suisun City — Signage

Signage under the Suisun City local zoning and planning code, with the controlling citations.

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Last reviewed: July 2, 2026

Overview

This page summarizes what the Suisun City Zoning Ordinance (Title 18) requires for signs in the city: who needs a sign permit, what sign types are allowed or prohibited, size/height and placement rules, special programs (uniform, creative, highway‑oriented, SSOD), and how nonconforming/abandoned signs are handled. The sign rules are administered through Chapter 18.44 (Signs) of Title 18 - ZONING; the ordinance also ties sign rules to the city's zoning districts (Table 18.06.01) and other development standards. (§ 18.44.010; § 18.06.010)

Note: This page stays inside the local zoning/planning ordinance. For building-code (Title 24) or electrical permits for illuminated signs, see the California Building Standards Code. (/us/california/building-codes)

What the code says (top-level rules)

  • Purpose and policy: signs must support wayfinding and commerce without creating visual clutter or unsafe conditions (§ 18.44.010) .
  • Message neutrality: the city will not regulate sign message content except to the minimum extent needed to identify sign type (§ 18.44.030) .
  • Permit trigger: most permanent signs require a sign permit; temporary signs and certain exempt signs do not but must meet size/duration/location limits (§ 18.44.040; § 18.44.050) .
  • General prohibition: permanent signs not expressly allowed are prohibited (§ 18.44.030) .
  • Prohibited types (citywide): billboards (new off‑site advertising), roof signs, animated/flashing digital signs (except limited time/temperature), inflatable balloon signs, signs in the public right‑of‑way, signs attached to poles/traffic devices, painted fence signs, and others (§ 18.44.060) .
  • Nonconforming and abandoned sign rules: maintenance, limited repairs allowed; major rebuilds must conform; abandoned signs have specific removal timeframes (§ 18.44.120) .

Throughout this page I link to the city's zoning overview, zoning map, and related topics — for example the word "zoning" below links to Suisun City's zoning page. (/us/california/suisun-city/zoning)

District-by-district (how sign allowances map to Suisun City zoning districts)

Suisun City's zoning districts are established in Table 18.06.01. The sign chapter mostly regulates by "land use type" (single‑family, multi‑family, nonresidential in residential zones, individual businesses, integrated developments), so the mapping below pairs the ordinance's land use categories to the city's actual district names so you can find the right rules for your property. See the city's zoning map for parcel‑specific zoning. (§ 18.06.010; Table 18.44.03)

NOTE: For civic/park/other districts (e.g., APS, P, OS, PQP) see the district purpose below and apply the land‑use sign allowances and any special program rules. (§ 18.28.060)

Residential districts — RL, RM, RH1, RH2, RMU

  • Purpose / where applied: low- to high-density residential, including mixed‑use residential areas (Table 18.06.01). (§ 18.06.010)
  • Typical permitted sign situations: home‑for‑sale/lease signs, home‑occupation signs, limited identity signs for apartment complexes. See the land‑use rows in Table 18.44.03: single‑family and multiple‑family entries set the building‑attached and freestanding allowances. (§ 18.44.080; Table 18.44.03)
  • Key dimensional standards:
    • Single‑family: building‑attached signs are not allowed; freestanding limited to up to 24 sq ft each and 4 ft high for neighborhood monument signs (two allowed) (§ 18.44.080; Table 18.44.03) .
    • Multi‑family: up to 16 sq ft total building‑attached; monument sign per street frontage up to 16 sq ft and 4 ft high (§ 18.44.080; Table 18.44.03) .
  • Where to verify: If your nonresidential use sits inside a residential zone, the "Nonresidential Uses in Residential Zoning Districts" row controls (smaller allowances — 12 sq ft, 4 ft height) (§ 18.44.080; Table 18.44.03) .

Commercial districts — CR, CSF, CMU, O

  • Purpose / where applied: retail, services, mixed‑use commercial and office districts; see Table 18.06.01. (§ 18.06.010)
  • Typical permitted uses: storefronts, offices, service businesses — sign allowances are larger than residential zones and scale with building frontage. (§ 18.44.080; Table 18.44.03)
  • Key dimensional standards:
    • Individual business (nonresidential): building‑attached signs calculated at 1 sq ft per linear foot of primary frontage (with a maximum); freestanding monument per street frontage 32 sq ft, max 12 ft height (integrated projects and large developments have alternate allowances) (§ 18.44.080; Table 18.44.03) .
  • Design expectations: material and architectural compatibility required; wall signs limited to no more than 75% of a wall's length and 15% of wall height for total sign height (§ 18.44.110; § 18.44.020 definitions) .

Planned / integrated / large developments — PUD, large shopping centers (any district where a multi‑tenant development exists)

  • Purpose / where applied: planned unit developments and any integrated development (three or more tenants) must adopt a Uniform Sign Program; creative sign programs are available for artistic exceptions. (§ 18.44.040(B–C))
  • Typical permitted uses: coordinated wayfinding and tenant identification signage; the uniform program can allow up to 10% deviation; a creative program can allow up to 20% deviation subject to findings. (§ 18.44.040(B–C))
  • Key dimensional standards: base allowances from Table 18.44.03 remain the starting point; approved programs set the site‑level deviations and design rules. (§ 18.44.080; Table 18.44.03) .

Park/Public/Civic districts — APS, P, OS, PQP

  • Purpose / where applied: parks, open space, public/quasi‑public uses. (§ 18.06.010; Table 18.28.01)
  • Sign considerations: event signs, community identification or directional signs can be authorized through community sign programs (city council) or as exempt signs for government notices. (§ 18.44.100; § 18.44.130)

Special Overlay: Special Sign Overlay District (SSOD) along Highway 12

  • Purpose / where applied: SSOD applies to commercially zoned properties near Highway 12 and allows a highway‑oriented pylon sign that may include off‑premise advertising (limited and regulated). The SSOD is an overlay mapping applied to commercial parcels adjacent to Highway 12, up to five SSODs allowed in corridor. (§ 18.44.090; SSOD rules)
  • Key limits: multitenant SSOD signs up to 150 sq ft total; single‑tenant up to 60 sq ft; heights up to 60 ft for multi‑tenant, and one‑and‑one‑half times adjacent structure height up to 35 ft for single tenant; setbacks ≥10 ft from highway ROW and ≥200 ft from residential zones; spacing ≥500 ft between highway‑oriented signs. (§ 18.44.090)

Quick reference table — most decision‑relevant standards

Topic / use Key numeric standard or rule Code Reference
General sign policy (message neutrality; permanent signs only if allowed) Message neutrality; permanent signs only if expressly allowed § 18.44.030
Single‑family lots (sign area / monument) Monument signs: 24 sq ft max; 4 ft high; 2 allowed for neighborhood Table 18.44.03; § 18.44.080
Multi‑family lots Building signs collective 16 sq ft; monument per frontage 16 sq ft, 4 ft high Table 18.44.03 (§ 18.44.080)
Individual nonresidential businesses 1 sq ft per linear foot primary frontage (max), freestanding up to 32 sq ft, 12 ft high Table 18.44.03; § 18.44.080
Integrated developments Uniform sign program required; 10% allowed deviation; creative program up to 20% § 18.44.040(B–C)
Highway/SSOD signs Single‑tenant 60 sq ft, multi‑tenant 150 sq ft; heights to 60 ft; spacing & setbacks apply § 18.44.090; SSOD details § 18.44.090
Prohibited (citywide) Billboards (new off‑site), roof signs, animated/flashing digital, painted fence signs, inflatable balloons, signs on ROW § 18.44.060
Exempt temporary signs A‑frame limited 6 sq ft; window signs ≤ 25% of window; temporary promo 40–60 sq ft per Table 18.44.01 § 18.44.050; Tables 18.44.01–02
Electronic/digital signs Max 50% of sign area may be digital; message change ≤ once per 8 seconds; brightness ≤ 0.3 fc above ambient at 250 ft § 18.44.110(B)
Nonconforming / abandoned Replacement allowed for maintenance; abandoned signs removed per timeframes (90 days/9 months rules) § 18.44.120

Practical guidance / plain-English interpretation (not verbatim code)

  • If you are a homeowner in a typical single‑family zone (RL, RM), you generally cannot put a new wall sign — instead you get small yard/sale flags, an A‑frame while open, or a small monument for neighborhoods — consult Table 18.44.03 and the exempt rules. (§ 18.44.080; § 18.44.050)
  • Small businesses in CR/CMU should calculate allowable wall sign area as 1 sq ft per linear foot of primary frontage (subject to a maximum) and can expect a 32 sq ft monument sign on a street frontage unless in an integrated center where a uniform sign program sets the specifics. (§ 18.44.080; Table 18.44.03; § 18.44.040)
  • Want something unusual (big pylon, creative sculpture sign, larger digital display)? Look at the Highway‑Oriented Sign Permit, SSOD, Creative Sign Program, or engage a Uniform Sign Program for multi‑tenant centers — each is discretionary and requires findings. (§ 18.44.040; § 18.44.090)
  • Digital signs are tightly constrained — they must limit animation, frequency, and brightness and include light sensors. Measure brightness per the code (0.3 footcandles over ambient at 250 ft). (§ 18.44.110(B))

Across the city the planning review will emphasize design compatibility, pedestrian scale (blade/awning signs), non‑interference with traffic sight lines, and consolidation of messages to reduce clutter. (§ 18.44.070; § 18.44.110)

(Design review and sign permits are separate processes. See the city's design review page for when design review is required.) (/us/california/suisun-city/design-review)

Checklist — what an applicant must satisfy before installing a permanent sign

  • Confirm the property's zoning (Table 18.06.01) and which land‑use sign row applies (§ 18.06.010) .
  • Determine whether the sign is exempt, temporary, or a permanent sign that triggers a sign permit (§ 18.44.040; § 18.44.050) .
  • Calculate allowable sign area/height using Table 18.44.03 or the specific SSOD/highway rules if applicable (§ 18.44.080; Table 18.44.03; § 18.44.090) .
  • Prepare design materials showing materials, mounting, illumination, and how sign meets design compatibility and proportionality rules (§ 18.44.070; § 18.44.110) .
  • If multi‑tenant, prepare or align with a Uniform Sign Program or request a Creative Sign Program (as needed) (§ 18.44.040(B–C)) .
  • For electronic/digital signage, include brightness control strategy and automatic dimming sensors per code (§ 18.44.110(B)(3)) .
  • Apply for sign permit (and any associated discretionary approvals), obtain required building/electrical permits for illuminated or structural work (building permits per Title 24) (§ 18.44.040; building code link) (/us/california/building-codes) .

Risks & Ambiguities

Issue Why it matters What to verify
Which zoning district row controls signage The sign chapter expresses allowances by land‑use type; you must map your parcel's zoning to the correct land‑use row (e.g., a business in a residential zone has smaller allowances) Confirm parcel zoning with the city and apply Table 18.44.03 accordingly (§ 18.06.010; § 18.44.080)
Whether a sign is "exempt" vs "requires permit" Exempt signs still have numeric limits and placement rules; misclassification can lead to abatement Verify exemption category and limits in § 18.44.050 and the specific size/time limits (A‑frame, window signs, temporary promos)
Electronic sign brightness and measurement method Code uses a specific ambient threshold at 250 ft; measurement errors trigger violations Provide photometric report and automatic dimming strategy to meet § 18.44.110(B) requirements
SSOD / Highway‑oriented eligibility SSOD is an overlay requiring application and council approval; highway permits have setbacks and spacing rules Confirm parcel is within an SSOD or within 100 ft of a state highway and follow § 18.44.090 / SSOD criteria
Nonconforming sign repairs Some repairs allowed; structural changes may require compliance Confirm allowed maintenance vs. prohibited alterations under § 18.44.120 and get director's guidance
Overlap with other approvals (encroachment, electrical) Sign installation may need other permits (ROW encroachment, electrical) Verify other permitting (city encroachment, building/electrical per Title 24) — Not found entirely within sign chapter; verify with jurisdiction (§ 18.44.050 notes)

Plain-English summary

Suisun City's sign rules (Title 18, Chapter 18.44) let ordinary homeowners and businesses install modest, well‑designed signs by right (subject to clear size, height, and placement limits), require permits for most permanent commercial signs, prohibit new billboards and distracting animated displays, and create discrete paths for larger or creative signage through uniform/creative/highway/SSOD programs; always check your parcel's zoning and Table 18.44.03 to know which numeric limits apply. (§ 18.44.080; Table 18.44.03; § 18.44.060)

Source References

  • Suisun City Zoning — Title 18 - ZONING, Chapter 18.44 (Signs), including: § 18.44.010 (Purpose) and § 18.44.020 (Definitions)
  • § 18.44.030 (Sign policies) — message neutrality; permanent‑only if allowed
  • § 18.44.040 (Permit requirements; Uniform/Creative/Community/Highway programs)
  • § 18.44.050 (Exempt signs — A‑frames, window signs, flags, etc.)
  • § 18.44.060 (Prohibited signs)
  • § 18.44.070 (General sign standards — measurement, illumination, placement)
  • § 18.44.080 and Table 18.44.03 (Allowed on‑site sign regulations; allowed permanent on‑site signs by land use type)
  • § 18.44.090 (Highway‑oriented signs) and SSOD rules (§ 18.44.090 details)
  • § 18.44.110 (Special standards by sign type — awnings, electronic signs, freestanding sign compatibility)
  • § 18.44.120 (Illegal, abandoned, and nonconforming signs)
  • Zoning district list (Table 18.06.01) — RL, RM, RH1, RH2, RMU, CR, CSF, CMU, O, APS, OS, P, PQP, PUD, DWSP — use Table 18.06.01 to determine which zoning rules apply to your parcel (§ 18.06.010)

Additional internal resources you may need (linked where these topics first appear above): Suisun City zoning & planning overview (/us/california/suisun-city), Suisun City Zoning (/us/california/suisun-city/zoning), Suisun City Development Standards (/us/california/suisun-city/development-standards), Suisun City Parking (/us/california/suisun-city/parking), Suisun City Design Review (/us/california/suisun-city/design-review), Suisun City Overlay Districts (/us/california/suisun-city/overlay-districts), Suisun City Historic Preservation (/us/california/suisun-city/historic-preservation), California Building Standards Code (/us/california/building-codes).

Sources

Retrieved passages

  • Suisun City Zoning Code (§ 3) High relevance
  • Suisun City Zoning Code High relevance
  • Suisun City Zoning Code (section shall) High relevance
  • Suisun City Zoning Code (section may) High relevance
  • Suisun City Zoning Code (chapter of) Medium relevance
  • Suisun City Zoning Code (§ 3) Medium relevance
  • Suisun City Zoning Code (Chapter 18.44) Medium relevance
  • Suisun City Zoning Code (chapter are) Medium relevance
  • Suisun City Zoning Code High relevance
  • Suisun City Zoning Code (§ 3) High relevance
  • Suisun City Zoning Code (Section 18.44.110) High relevance
  • Suisun City Zoning Code (Section 18.44.070) High relevance
  • Suisun City Zoning Code (§ 3) High relevance
  • Suisun City Zoning Code (section are) High relevance
  • Suisun City Zoning Code (section may) Medium relevance
  • Suisun City Zoning Code (§ 3) Medium relevance
  • Suisun City Zoning Code (Chapter 18.42) Medium relevance
  • Suisun City Zoning Code (Chapter 18.42) Medium relevance
  • Suisun City Zoning Code (section shall) Medium relevance
  • Suisun City Zoning Code (section may) Medium relevance
  • Suisun City Zoning Code (Chapter 18.42) Medium relevance
  • Suisun City Zoning Code (Title 18) Medium relevance

Cited sections

Frequently asked questions

What kinds of signs can I put up on a single‑family lot in Suisun City?

For single‑family lots the ordinance forbids building‑attached advertising signs; neighborhood identification monument signs are allowed (up to 24 sq ft each, 4 ft high, up to two) and typical temporary/exempt signs (for sale, A‑frame while open) are allowed under the exempt rules. See Table 18.44.03 and § 18.44.080.

How do I calculate allowed wall‑sign area for a storefront in Suisun City?

For a typical nonresidential storefront the code uses a frontage ratio — generally 1 sq ft of sign area per linear foot of primary building frontage (subject to a maximum in the table), plus limits on wall sign scale (no more than 75% of wall length and 15% of wall height). See Table 18.44.03 and § 18.44.110.

Are digital or electronic signs allowed in Suisun City?

Electronic/digital signs are allowed in limited form: digital changeable copy may be up to 50% of the total sign area, messages may not change more than once every 8 seconds, and brightness must not exceed 0.3 footcandles above ambient measured at 250 ft; signs must have a light sensor/dimming control. (§ 18.44.110(B))

Can I put billboards or off‑site commercial advertising on private property?

No — new off‑site commercial signage on private property is prohibited except as specifically allowed (e.g., limited SSOD/Highway‑oriented allowances). Existing billboards are handled as nonconforming signs per § 18.44.120. (§ 18.44.100; § 18.44.120)

Do I need a uniform sign program for a shopping center with multiple tenants?

Yes. Any integrated development of three or more tenants that shares parking/landscape/public space must have a Uniform Sign Program; deviations up to 10% from chapter standards are possible through that program. (§ 18.44.040(B))

What signs are exempt from a city sign permit?

Exempt signs include: conforming sign face replacements, official governmental traffic/legal notices, temporary noncommercial signs within size limits, A‑frame signs (max 6 sq ft, max 3 ft high, one per tenant outside ROW), flags within size limits, and window signs up to 25% of a window. But exempt signs must still meet the numeric limits and other codes (e.g., electrical permits for illumination). (§ 18.44.050)

How are abandoned or nonconforming signs handled?

Abandoned signs must be removed or have copy blanked within set timeframes (e.g., structure/copy removed within 90 days for vacated businesses); nonconforming signs can be maintained but not structurally altered unless brought into conformance. The city may abate and lien for noncompliance. (§ 18.44.120)

Can a business put temporary promotional banners or grand‑opening banners up?

Yes — temporary promotional signs are allowed with limits. Temporary promotional displays generally have a maximum cumulative display period (e.g., promotional signs up to 90 days/year; temporary business transition signs up to 45 cumulative days/year) and size limits defined in Tables 18.44.01–02. (§ 18.44.070; § 18.44.050; Tables)

What if I need a freestanding sign larger than the standard allowance because my site fronts a state highway?

Properties within 100 ft of a designated state highway may apply for a Highway‑Oriented Sign Permit; the permit allows larger/taller freestanding signs and consolidation of messages, but requires council approval and complies with setbacks, spacing, area, and height rules, and must comply with Caltrans and the California Outdoor Advertising Act as applicable. (§ 18.44.090; § 18.44.040(E))

Who decides creative or SSOD signage and what findings are required?

The planning commission decides Creative Sign Program requests (up to 20% deviation) and the city council decides SSOD designations and highway‑oriented sign permits; findings must show consistency with the general plan and that deviations contribute positively to character without negatively impacting surrounding properties. (§ 18.44.040(B–D); § 18.44.090)

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