Solano County Zoning, Planning & Building Codes

Last reviewed: July 3, 2026

Overview

This page orients you to how Solano County regulates land use and development in its unincorporated areas. The County’s zoning ordinance is codified in the Solano County Zoning Regulations (Chapter 28) and establishes district families (residential, agricultural, commercial, industrial, resource/conservation), development standards (setbacks, height, FAR/coverage, parking), special overlay and policy-plan tools, and the County permit/review paths (administrative permits, use permits, Planning Commission and Board actions). Key procedural authorities are the Director of Resource Management (Zoning Administrator) and the Planning Commission. See § 28.22A and the administrative rules at § 28.115–§ 28.118 for the basic structure and authorities; .

How Solano County's code is organized

• The zoning ordinance is organized as Chapter 28 of the Solano County code (table-driven land use tables, district chapters, and an Article for site development standards). The main land‑use tables and district lists appear in Table 28.22A and the district chapters that follow (e.g., residential, commercial, industrial, agricultural), and the site standards and special rules appear in Article IV (beginning at § 28.90). See § 28.22A and Article IV (starting § 28.90) for the tabular layout and cross‑references; .
• Administrative & decisionmaking structure: the Planning Commission reviews and recommends on major actions (§ 28.115) and the Director of Resource Management serves as Zoning Administrator and administers ministerial and many discretionary functions (§ 28.117–§ 28.118); .
• The code uses a Table-of-Allowed-Uses approach (Table 28.22A) where each use row identifies the permit required and points to additional regulations (land‑use rules in Article III and other chapters) — see § 28.22A; .

Zoning district families (what you’ll actually see on the zoning map)

The ordinance breaks the unincorporated county into families of districts. Below are the main families and where to read the County’s intent and allowed uses:

• Agricultural districts — examples: A-SV-20, ATC, ATC‑NC (Suisun Valley and Agricultural Tourist Center variants). Purpose and special rules for Suisun Valley are in § 28.23.10–§ 28.23.60 and the development standards are collected in Tables 28.23B and 28.23C; , .
• Residential districts (Traditional Community / Rural) — e.g., R-R 2-1/2, R-R 5, R-R 10, and other R districts appear in the residential chapter (see § 28.32 and the development tables such as Table 28‑31B/28‑31C); setbacks, accessory-structure rules and lot-size rules are captured in those tables and cross‑referenced to § 28.93 for measurement rules; , .
• Commercial districts — C‑H, C‑N, C‑R, C‑R‑L, C‑S, C‑O; purposes and permitted uses are in § 28.41.11 and Tables 28.41A/28.41B provide district‑specific standards (setbacks, height); see § 28.41.11 and Table 28.41B; , .
• Industrial / Manufacturing districts — M‑L, M‑G‑1/2, M‑G‑3, I‑WD, I‑AS and others; development standards including front/side/rear setbacks, height limits and use‑specific controls are in Table 28.42B and § 28.43 (I‑AS); , .
• Resource & conservation districts — W (Watershed and Conservation) and MP (Marsh Protection); purpose and protective standards are in § 28.50–§ 28.52 and § 28.104 for marsh development permits; , .
• Overlay / special plan tools — the County uses Policy Plan Overlay (suffix “‑PP”) and specific plans to create customized standards for an area; the policy plan overlay’s procedures, required findings and contents are in the Policy Plan Overlay rules (see § 28.111 and the Policy Plan Overlay subsections describing purpose, applicability and adoption findings); , .

(Where a table or district chapter is named above, consult the referenced Table or § for the precise numeric standards in your location.)

Citywide development standards (how the County regulates bulk and site design in unincorporated areas)

• Setbacks and measurement rules: minimum front/side/rear setbacks are specified per district in the development‑standards tables (e.g., Table 28.23B for A‑SV‑20 and ATC districts; Table 28.41B for commercial districts). Setback measurement rules, allowed projections and exceptions are handled in § 28.93 and referenced in the tables; see § 28.23.40 (Table 28.23B) and § 28.93 for measurement/exceptions; , .
• Height limits: district tables list height caps (commonly 35 ft in many R and A districts; 50 ft or greater in some industrial districts with conditions). Height exceptions and airport‑related limits are in § 28.93 and § 28.99; see Table 28.23B and Table 28.42B for examples and § 28.93/§ 28.99 for exceptions; , .
• Floor area ratio (FAR) and lot coverage: many zones (notably ATC/ATC‑NC) show explicit FAR limits in the tables (e.g., 0.5 with water/sewer; 0.3 without), recorded in Table 28.23B/28.23C; see § 28.23.40 and Table 28.23B/28.23C for FAR values; , .
• Parking: the County centralizes parking requirements in § 28.94; nearly every district’s table points to § 28.94 for off‑street parking requirements and notes when special parking rules (e.g., Suisun Valley parking districts) apply; consult § 28.94 and the district tables (e.g., § 28.23.40 referencing parking) for specifics. Link: Solano County Parking — see § 28.94; , .
• Signs & landscaping: signs are regulated in § 28.96 and landscaping/screening standards are in the site‑development Article (see § 28.90+ for cross references); link: Solano County Development Standards and Solano County Landscaping and Screening. See § 28.96 and the site‑development Article referenced in district tables; , .
• Design & discretionary review: the code requires Architectural Approval for certain uses under § 28.102 and identifies where design guidelines and design review apply (for example Suisun Valley design guidelines and policy plan overlay design requirements in § 28.23.60 and Policy Plan Overlay rules); link: Solano County Design Review. See § 28.102 and § 28.23.60 for examples; , .

Specific plans & overlays (how the County customizes regulation for an area)

• Policy Plan Overlay District: a formal overlay tool that is added to a base district with a “‑PP” suffix on the zoning map; it requires an adoption ordinance, a development plan that integrates zoning/master/precise plans and design review, and specific findings by the Board of Supervisors for adoption (§ 28.111 and the Policy Plan Overlay text); see § 28.111 and the Policy Plan Overlay substantive checklist (required narrative, standards and findings); .
• Specific Plans & Area Plans: the code cross‑references specific plans and allows standards in specific plans to supersede or add to district rules; the Policy Plan Overlay and district chapters reference conformity with any applicable specific plan as an adoption condition (see Policy Plan Overlay findings); see § 28.111 and the overlay adoption findings; .
• Marsh and Suisun Marsh rules: within the Suisun Marsh, specialized marsh development permits and the Suisun Marsh Local Protection Program rules apply; the ordinance sets application content, hearing and findings for marsh permits in § 28.104 and the marsh chapters (see marsh permit procedures and public notice rules); .

See Solano County Overlay Districts for more on overlays and Solano County Historic Preservation where relevant.

Building permits & review (the path from application to permit in unincorporated areas)

• Permit types & table guidance: Table 28.22A lists allowed uses and the typical permit required (A = by right, AP = Administrative Permit, MUP = Minor Use Permit, UP = Use Permit). Additional special permits (marsh development permits, policy plan approvals) have their own sections; see § 28.22A for the table structure and cross references; .
• Architectural approval / design review: certain projects require architectural approval under § 28.102; design guidelines (for Suisun Valley, other areas) and Policy Plan Overlay design requirements also apply and the Director can approve minor design alterations that are substantially in accord with an approved policy plan overlay (§ 28.111(g)); see § 28.102 and § 28.111(g); , .
• Ministerial vs discretionary: the Director (Zoning Administrator) issues ministerial zoning clearances and many administrative permits; discretionary permits (Use Permits, zone changes, specific plans) are heard by the Planning Commission and/or Board of Supervisors per the authorities set out in § 28.115–§ 28.118; .
• Building permits: a building permit is required prior to construction and the County coordinates building‑code review with zoning (the code repeatedly notes that building permits must comply with the Building Code and other County department approvals); see § 28.102 (architectural approval references) and the repeated “Building Permits” note in district chapters; link: California Building Standards Code and consult district tables that cross‑reference the Building Code; .
• Appeals & timelines: discretionary actions include public‑notice and hearing requirements (e.g., public notices per § 28.04) and administrative appeal paths (appeals to the Board and timelines tracked per the Permit Streamlining Act language used in marsh permit procedures); see the procedural sections and the marsh permit public notice/appeal language at § 28.104–§ 28.112; , .

For practical permit navigation: start with Table 28.22A to identify the required permit for your proposed use, confirm district development standards in the applicable Table (e.g., Table 28.23B/28.41B/28.42B), and then check the site standards (Article IV, § 28.90+) and special sections (marsh, Suisun Valley, overlays).

State housing law in Solano County (how statewide rules interact with the County code)

• Accessory dwelling units (ADUs & JADUs): State ADU law preempts restrictive local rules in several areas (size, setbacks, parking limits). The County’s code treats accessory dwellings separately in the residential and agricultural tables and accessory‑dwelling references appear in Table 28.23C and elsewhere, but Solano County must implement ADU law consistent with state mandates (local ADU process references in district accessory building notes and cross‑references to Section 28.01 definitions). For statewide ADU defaults and limits, see the statewide guidance; link: California ADU law. Consult the County’s accessory‑dwelling entries in the district tables (e.g., Table 28.23C) and the general accessory rules (see Table 28‑31C and Table 28‑23C); , .
• SB 9 / lot‑splits & Duplex ministerial rules: The County’s code sets minimum lot areas and indicates where minimum parcel size may be modified by permit in agricultural and rural zones (see notes in Table 28.23B and § 28.23.40). Whether SB 9 ministerial lot‑split and duplex rules apply requires confirming specific County implementing rules; the code contains minimum lot areas and procedures for reducing minimum parcel size by Use Permit in agricultural zones (see § 28.23.40 notes and references to subdivision rules). Because SB 9 is state law, check the County’s zoning counterparty rules and planning office guidance for explicit implementing language; see Table 28.23B notes on parcel size and § 28.23.40; .
• Density bonus & housing incentives: The County’s district tables do not obviate state density‑bonus rights; developers seeking density bonus adjustments must follow state law and the County’s discretionary review processes for any local concessions or waivers. The code does not explicitly reproduce the density bonus statute in the retrieved sections; verify with the County on local implementing procedures (not found in the retrieved materials).
• Rent control and tenant protections: the Solano County zoning code regulates land use and development, not rent stabilization. The zoning code excerpts do not establish rent‑control provisions; verify housing/rent policy with County ordinances outside Chapter 28 (Not found in retrieved zoning materials).

See the State links: California housing laws and California ADU law for statewide requirements; for local application check the accessory/building entries in the County tables (e.g., Table 28.23C and Table 28‑31C) for the County’s accessory‑dwelling and accessory building parameters; , .

Practical orientation: where to look first for answers about a specific property in unincorporated Solano County

1. Identify the property’s zoning notation on the County zoning map (note: the code applies only to unincorporated areas). Then consult:
   • The Table of Allowed Uses (Table 28.22A) to see the permit type required for your use (A/AP/MUP/UP) — § 28.22A; .
   • The district chapter and its development‑standards table (e.g., Table 28.23B for Suisun Valley, Table 28.41B for commercial) for setbacks, height, FAR and lot area — e.g., § 28.23.40 (Table 28.23B), § 28.41.30 (Table 28.41B); , .
   • Article IV (site development standards) for parking (§ 28.94), signs (§ 28.96), architectural approval (§ 28.102) and other cross‑cutting standards; .
2. Confirm any overlay or specific‑plan rules (look for a “‑PP” suffix or references to a Specific Plan in the district or the zoning map) — Policy Plan Overlay rules and required findings are at § 28.111 and related Policy Plan Overlay subsections; .
3. For permit path and appeals, consult the procedural chapters (Zoning Administrator duties, Planning Commission roles) and the public notice/hearing rules — see § 28.115–§ 28.118 for decision authorities and procedural cross‑references; .

Information gaps / items to verify with the County

• The retrieved ordinance excerpts show detailed tables and many district rules, but I did not retrieve a single consolidated “ADU chapter” or explicit County implementation text for SB 9 or the state density bonus — verify with the Department of Resource Management for the County’s explicit SB 9 and density bonus implementing procedures (Not found in retrieved materials).
• Rent‑control / tenant‑protection ordinances are not located in the retrieved Chapter 28 excerpts; those would be in other County ordinances if they exist (Not found in retrieved materials).

Source References

• Solano County Zoning Regulations, Table of Allowed Uses and district chapters, Chapter 28 (see Table 28.22A and accompanying district chapters) — § 28.22A;
• Suisun Valley Agricultural Districts and development standards (Tables 28.23B/28.23C) — § 28.23.10–§ 28.23.60;
• Commercial district development standards (Table 28.41B) and district purposes — § 28.41.11, § 28.41.30; ,
• Industrial district standards (Table 28.42B) and Industrial–Agricultural Service (I‑AS) district — § 28.42/§ 28.43; ,
• Policy Plan Overlay District rules and adoption findings — Policy Plan Overlay provisions (see the Policy Plan Overlay subsections and adoption findings) — § 28.111 and related Policy Plan Overlay text;
• Parking, architectural approval and site development cross‑references (Article IV and § 28.90+; § 28.94, § 28.96, § 28.102) — see district tables’ cross references;
• Planning Commission, Zoning Administrator and Director authorities — § 28.115, § 28.117, § 28.118;