Solano County — Zoning

Last reviewed: July 3, 2026

Overview

Solano County’s zoning regulations for the unincorporated areas are contained in the County Zoning Code (Chapter 28). The ordinance establishes specific base districts (agricultural, residential, commercial, industrial, resource, park), overlay/policy plan overlays, and an adopted set of Solano County Zoning Maps that control where each district applies (§ 28.13, § 28.11) . Practical project checks typically focus on allowed uses (Table/look‑ups), dimensional standards (setbacks, height, lot area), special-area rules (Suisun Marsh, Suisun Valley), and discretionary processes (use permits, design review).

Before you act you will need to verify districting on the official Solano County Zoning Map (§ 28.11) , confirm which Table of Allowed Uses applies, and then read the specific development standards that apply to that district (see the County’s Development Standards and the ordinance tables such as TABLE 28.21A, TABLE 28.23A, and TABLE 28.31B) . Off‑street parking must meet the County parking rules (§ 28.94) — see the County Parking page for guidance . Architectural approval / design review rules are applied in several districts and are administered under § 28.102 and district-specific design review sections — see the County Design Review page for how that process interacts with zoning .

District-by-district primer (unincorporated Solano County)

Below are the most decision‑relevant districts from the Zoning Code. Each subsection lists the stated purpose, typical allowed uses, key dimensional standards and where the district appears in the ordinance. All rules cited apply only in the unincorporated areas.

Agricultural Districts (A‑20, A‑40, A‑80, A‑160)

• Purpose: Preserve and promote agriculture and the family farm; allow agricultural support uses while excluding incompatible uses (§ 28.21.11) .
• Typical permitted uses: crop production, grazing, agricultural processing, nurseries, wineries (see TABLE 28.21A for the full list) (§ 28.21.20, Table 28.21A) .
• Key development standards: County requires compliance with Article IV site-development rules (parking, signs, setbacks) and district tables; architectural approval may be required (§ 28.21.20, § 28.102) .
• Where it applies: Rural majority of unincorporated county; see TABLE 28.21A for permit thresholds (§ 28.21.20) .

Agriculture — Suisun Valley & Agricultural Tourist Center (A‑SV‑20, ATC, ATC‑NC)

• Purpose: Preserve Suisun Valley’s viticulture/agricultural character and allow agritourism where compatible (§ 28.23.10–.12) .
• Typical permitted uses: vineyards, farm stands, wineries, farm stays, small retail and tourist‑serving uses; many uses listed in TABLE 28.23A and subject to special standards in § 28.23.50 and TABLES 28.23B/C .
• Key standards: accessory building setbacks and heights are specified in TABLE 28.23C (e.g., accessory building rear setbacks 20 ft in A‑SV‑20; height limit generally 35 ft) (§ 28.23C, TABLE 28.23C) . Design review is required for all new construction requiring a building permit in A‑SV‑20 and ATC districts (§ 28.23.60) — see the County Design Review page for process details .
• Special: Agritourism uses have event, parking, water and sanitation, and operation limits set out in § 28.23.50 .

Rural Residential (R‑R) — example: R‑R 2‑1/2, R‑R 5, R‑R 10

• Purpose: Provide low‑density residential lots in rural areas and set minimum lot sizes and standards (§ 28.31 family of sections, TABLE 28.31B) .
• Typical permitted uses: single‑family dwellings, accessory dwellings (subject to ADU rules and § 28.72.10), agricultural accessory uses where allowed (§ 28.31B, § 28.72.10) .
• Key dimensional standards (TABLE 28.31B):
  • Minimum lot area: R‑R 2‑1/2 = 2.5 acres, R‑R 5 = 5 acres, R‑R 10 = 10 acres.
  • Setbacks: front 30 ft (and 50 ft from street centerline unless otherwise noted), side 10 ft, rear 25 ft.
  • Height limit: 35 ft (typical) (§ TABLE 28.31B) .
• Note: ADUs and secondary dwellings have specific size/approval rules (see § 28.72.10) and state ADU law — see California ADU law for state requirements that interact with local zoning .

Residential — R‑TC family and R‑TC‑MF (Traditional Community / Multi‑Family)

• Purpose and uses: Provide a range from single‑family lots down to small‑lot and multi‑family areas; district list and subtypes are identified in the district table (§ 28.13/Article II) .
• Standards: See the R‑district tables and TABLE 28.31B (lot area, frontage, setbacks and ADU rules) (§ 28.31B) .

Commercial Districts (C‑H, C‑N, C‑R, C‑R‑L, C‑S, C‑O)

• Purpose: Each commercial district has a focused intent — C‑H for highway‑serving uses, C‑N for neighborhood convenience retail, C‑R/C‑R‑L for recreation‑oriented commerce in/outside Suisun Marsh, C‑S for heavier commercial services, and C‑O for offices (§ 28.41.11) .
• Uses and permits: Table 28.41A lists allowed uses and the land use permit required (A, AP, MUP, UP, etc.) and calls out Marsh Development Permit triggers in the Suisun Marsh (§ 28.41.20) .
• Key standards: Site development standards: parking (§ 28.94), signs (§ 28.96), and any marsh rules for projects inside the Suisun Marsh Management Area (§ 28.104) .

Manufacturing / Industrial (M‑L, M‑G, I‑WD, I‑AS)

• Purpose and allowed uses: The manufacturing/industrial article (TABLES 28.42A/28.42B) defines what is allowed in M‑L (limited manufacturing), M‑G (general manufacturing), the I‑WD (water‑dependent industry), and I‑AS (industrial‑agricultural service) (§ 28.42.20, § 28.43) .
• Key specifics: In many industrial districts, uses must be wholly within an enclosed building except where agriculture, outdoor storage/parking/loading, or specific use permits allow otherwise; manufacturing processes may be limited to gas/electric power where stated (§ 28.42.20, TABLE notes) . I‑WD applies special criteria requiring that a use truly be water‑dependent and comply with Suisun Marsh and General Plan policies (§ 28.42 text on water‑dependent industry) . I‑AS references its own standards and the Northeast Dixon design guidelines where applicable (§ 28.43.30) .

Park District (P)

• Purpose and uses: Preserve land for outdoor recreation and compatible recreational uses; allowed uses and permit requirements appear in TABLE 28.61A (§ 28.61) .

Resource & Conservation Districts (W, MP, etc.) and Suisun Marsh (A‑SM)

• Purpose: Protect watershed, marsh and other sensitive resource lands; special tables (e.g., TABLE 28.51A for the W District) lay out allowed agricultural and conservation uses, and Marsh Development Permits are required for projects in the Suisun Marsh (§ 28.51A, § 28.104) .

Overlay & Policy Plan Overlays (‑PP, TRA, Middle Green Valley, etc.)

• Purpose: Overlay districts modify or add standards to an underlying base district (for example, to create area‑specific development rules or a combined zoning/master plan). The ordinance treats policy plan overlays as a formal overlay symbol “‑PP” and requires a detailed development plan and findings for approval (§ 28.68) . See the County Overlay Districts page for how overlays commonly affect approvals.

Quick reference table — common decision standards and code references

Checklist — what an applicant must satisfy (unincorporated Solano County)

• Confirm the parcel’s base zoning and any overlays on the official Solano County Zoning Map (§ 28.11) .
• Consult the applicable Table of Allowed Uses (e.g., TABLE 28.21A, TABLE 28.23A, TABLE 28.41A, TABLE 28.42A) and identify whether the proposed use is A / AP / MUP / UP / prohibited (§ 28.21.20, § 28.23.30, § 28.41.20, § 28.42.20) .
• Read the development‑standards table for that district (setbacks, lot area, height — e.g., TABLE 28.31B for many R‑districts) and confirm compliance (§ 28.31B) .
• Check parking (§ 28.94) and sign (§ 28.96) standards and provide required calculations and plans; coordinate with County Parking guidance .
• Determine permit pathway: ministerial building permit vs. Administrative Permit vs. Minor Use Permit vs. Use Permit; prepare required findings and environmental review if applicable (§ 28.21.20, § 28.106, § 28.111) .
• If in A‑SV‑20 or ATC, plan for design review (architectural approval) as required (§ 28.23.60) and consult the Suisun Valley design guidelines — see the County Design Review page .
• If in Suisun Marsh or proposing marsh‑affecting development, check Marsh Development Permit rules (§ 28.104) and Suisun Marsh Act implications (§ 28.42.20) .
• For ADUs or accessory dwellings, confirm local sizing and permit rules (see § 28.72.10) and state ADU rules (California ADU law) .
• Prepare site plan, elevations, landscape/screening, parking plan, and any performance‑standard responses (noise, dust, drainage) required by the district and § 28.90‑series standards; consult Development Standards .
• Verify conformity with the California Building Standards Code (Title 24) for building permit submittal — zoning clearance is necessary but building code compliance is a separate requirement .

Risks & Ambiguities

Plain‑English summary

Solano County’s zoning code says where things may be built in the unincorporated county by mapping discrete base districts (agricultural, residential, commercial, industrial, resource and park) and overlay zones, lists what each district allows, and sets the dimensional and site standards (lot size, setbacks, height, parking, signs) you must meet or get a permit to change; always check the official zoning map and the applicable TABLE of ALLOWED USES first (§ 28.11, § 28.21.20, TABLE 28.31B) .

Source References

• Solano County Zoning Code, Districts and Tables (district list and map adoption): § 28.13, § 28.11 .
• Agricultural Districts (A‑20/A‑40/A‑80/A‑160) and TABLE 28.21A: § 28.21.10–.30, § 28.21.20, TABLE 28.21A .
• Suisun Valley and Agricultural Tourist Center rules (A‑SV‑20, ATC, ATC‑NC), TABLE 28.23A, TABLE 28.23B/C, design review requirement: § 28.23.10–.60, TABLE 28.23A/C .
• Rural residential development standards and accessory dwelling references (TABLE 28.31B and § 28.72.10): TABLE 28.31B (§ 28.31B) .
• Commercial districts and TABLE 28.41A: § 28.41.11, § 28.41.20, TABLE 28.41A .
• Manufacturing / Industrial districts and water‑dependent industry rules: § 28.42.20, I‑WD discussion, TABLE 28.42A/28.42B .
• Industrial‑Agricultural Service (I‑AS): § 28.43 and TABLE 28.43A .
• Park District (P) and TABLE 28.61A: § 28.61 .
• Overlay / Policy Plan Overlay rules (‑PP): § 28.68 (policy plan overlay description) .
• Parking and loading requirements referenced in district tables: § 28.94; signs: § 28.96 .
• Marsh Development Permit references and Suisun Marsh rules: § 28.104, marsh citations in the industrial/commercial sections (see § 28.42.20, § 28.41.20) .
• Administrative, use permit and governing procedures (Zoning Administrator, Planning Commission): §§ 28.115–28.118, permit procedure references (§ 28.106, § 28.111) .
  (These citations are to the provided Solano County Zoning Code materials extracted from the County Chapter 28 file) .

Retrieved passages

• Solano County Zoning Code (Section 28-99) High relevance show source text
• Solano County Zoning Code (Chapter 28) High relevance show source text
• CBC § 28.94 (Chapter 28) Medium relevance show source text
• Solano County Zoning Code (Chapter 28) Medium relevance show source text
• Solano County Zoning Code (Section 28-99) Medium relevance show source text
• Solano County Zoning Code (Section lists) Medium relevance show source text
• CBC § 28.72.10 (Section 28.72.10) Medium relevance show source text
• Solano County Zoning Code (Section and) Medium relevance show source text

Cited sections

• Solano County Zoning Code, Districts and Tables (district list and map adoption): § **28.13**, § **28.11** .
• Agricultural Districts (A‑20/A‑40/A‑80/A‑160) and TABLE **28.21A**: § **28.21.10–.30**, § **28.21.20**, TABLE **28.21A** .
• Suisun Valley and Agricultural Tourist Center rules (A‑SV‑20, ATC, ATC‑NC), TABLE **28.23A**, TABLE **28.23B/C**, design review requirement: § **28.23.10–.60**, TABLE **28.23A/C** .
• Rural residential development standards and accessory dwelling references (TABLE **28.31B** and § **28.72.10**): TABLE **28.31B** (§ **28.31B**) .
• Commercial districts and TABLE **28.41A**: § **28.41.11**, § **28.41.20**, TABLE **28.41A** .
• Manufacturing / Industrial districts and water‑dependent industry rules: § **28.42.20**, I‑WD discussion, TABLE **28.42A/28.42B** .
• Industrial‑Agricultural Service (I‑AS): § **28.43** and TABLE **28.43A** .
• Park District (P) and TABLE **28.61A**: § **28.61** .
• Overlay / Policy Plan Overlay rules (‑PP): § **28.68** (policy plan overlay description) .
• Parking and loading requirements referenced in district tables: § **28.94**; signs: § **28.96** .
• Marsh Development Permit references and Suisun Marsh rules: § **28.104**, marsh citations in the industrial/commercial sections (see § **28.42.20**, § **28.41.20**) .
• Administrative, use permit and governing procedures (Zoning Administrator, Planning Commission): §§ **28.115–28.118**, permit procedure references (§ **28.106**, § **28.111**) .
• SolanoCounty_ZoningCode.md