Union City — Zoning

Last reviewed: July 2, 2026

Overview

This reference summarizes what the Union City Zoning Ordinance (Title 18) actually says about zoning: how the City defines and maps zoning districts, the major district categories, where to find permitted uses and dimensional standards, and the administrative processes that control changes and project approvals. The Zoning Ordinance establishes districts such as residential (RS / RM), commercial (CPA, CN, CC, CVR, CUL, CMU), industrial (MG, ML, MS), and special / overlay zones and area-specific chapters (for example, Union Landing, the 511 Area, and DIPSA) and ties process rules (site development review, administrative review, use permits) to those districts. See the ordinance purpose and scope at § 18.04.010.

This page links you to the related local pages you will likely need while working through a project (parking, development standards, design-review, overlays, ADUs, signage, etc.), and explains where in the code to look for specific requirements. For procedural and building-code questions see the separate pages (and the California Building Standards Code).

How Union City organizes zoning (plain structure and legal anchors)

• The ordinance is published as Title 18 — Zoning; the title purpose and minimum-standards rule appears at § 18.04.010.
• The City maintains an official zoning map and treats that map as part of the ordinance; map amendments are recorded and the map is kept on file with the City Clerk. If a boundary is uncertain, the ordinance directs reliance on lot lines, map scale, or a Planning Commission determination. See the map and boundary rules in the General Provisions chapter (Chapter 18.04, range starting at § 18.04.010).
• Administrative and project-review procedures that apply across districts include Administrative Site Development Review (Chapter 18.72; see § 18.72.010) and Site Development Review (Chapter 18.76; see § 18.76.010) — both apply to projects unless otherwise exempted.
• Where the ordinance refers to design, signage, or parking rules those requirements live in other Title 18 chapters (for example, sign plans and sign rules in Chapter 18.30; see § 18.30.100 for sign-plan requirements). Link-outs to local topic pages are included throughout (for example, Union City Parking, Union City Design Review, Union City Development Standards, Union City Overlay Districts, Union City ADUs, and Union City Signage).

District-by-district breakdown (purpose, typical permitted uses, key dimensional standards, where it applies)

Note: Each district description below synthesizes the ordinance text and points to the controlling chapter/sections. For parcel-specific permits and numeric checks, always verify the parcel’s map designation and applicable overlay(s).

Residential districts — RS and RM (Chapter 18.32)

• Purpose: Provide locations for single-family and multi-family housing and regulate bulk, setbacks, parking and related residential standards (see § 18.32.010).
• Typical permitted uses: single-family dwellings, duplexes and multifamily types as set by the RS / RM tables (see Chapter 18.32). Accessory dwelling units are covered separately in Chapter 18.34.
• Key dimensional / development rules you will see in the chapter: minimum yards, lot coverage/building coverage rules, and special provisions for accessory structures and SB 9 units (see Sections such as § 18.32.020 (various lot standards referenced) and § 18.32.160 for parking). Garage and landscaping specifics appear across the residential rules (see § 18.32.115, § 18.32.160).
• Where it applies: Citywide mapped residential parcels. Verify exact subdistrict (RM‑1500, R‑5000, etc.) on the official zoning map. For SB 9 and ADU exemptions see chapters referenced in the residential rules.

Commercial districts — CPA, CN, CC, CVR, CUL (Union Landing), CMU (Chapter 18.36; Union Landing in Chapter 18.39)

• Purpose: Provide locations for neighborhood to regional commercial activities; the chapter lists allowed retail, professional, restaurants and associated services (see § 18.36.010).
• Typical permitted uses: banks, apparel and accessory stores, full‑service and fast‑food restaurants, food stores, business services, certain entertainment/recreation uses — each C subtype (CPA, CN, CC, CVR) has a columned use table that marks permitted/conditional uses (see Chapter 18.36). The Union Landing CUL district has its own use tables and additional development/performance criteria in Chapter 18.39 (see § 18.39.030 and uses tables such as Table 18.39.040 / 18.39.050).
• Key dimensional / development rules: Commercial parking standards are set in Chapter 18.36 (see § 18.36.150), loading in § 18.36.140, outdoor dining and related standards in § 18.36.190; sign plans are required (see § 18.30.100). Shared parking for mixed‑use ground‑floor commercial is evaluated case‑by‑case (see § 18.36.150). Link: Union City Parking.

Industrial districts — MG (General Industrial), ML (Light Industrial), MS (Special Industrial) (Chapter 18.40)

• Purpose: Provide locations for industrial and high‑intensity uses with performance standards to control nuisance impacts (see § 18.40.010).
• Typical permitted uses: manufacturing, assembly, warehousing, distribution; ML and MS are tuned to lighter industrial / office‑park uses; specific uses and whether they are Permitted / Administrative Use Permit / Use Permit are set in Table 18.40.020 (Land Use Regulations—Industrial Districts).
• Key dimensional / performance rules: performance criteria limit smoke, vibration, noise, hazardous materials and diesel equipment (see the industrial performance and prohibitions in Chapter 18.40). Loading, fencing, screening and landscaping rules in other chapters apply (see Chapter 18.24 and landscape standards).

Employment / Mixed-Use specialties — CMUE and SEE (Table 18.41.060 / Chapter 18.41)

• Purpose: Corridor Mixed‑Use Employment (CMUE) and Station East Employment (SEE) districts set tailored FAR, lot size, frontage, required building stories and height limits to encourage employment‑oriented mixed‑use urban forms. Key numeric rules appear in Table 18.41.060 (site area, FAR min/max, street frontage and setbacks, height limits). Notable examples: FAR minimum/maximum and maximum heights shown in Table 18.41.060; interior‑adjacency buffers to residential uses (50 ft or 20 ft depending on district) are specifically called out. See § 18.41.060 for the table.

Private Institutional — PI (Chapter 18.51)

• Purpose: Locate private institutional uses (churches, private schools, continuing care retirement communities) with rules tied to parking, signs and site review (see § 18.51.010).

Specific plans & special study areas

• 511 Area Specific Plan: a Chapter/area with its own development standards and mandatory findings for Planning Commission review (see Chapter 18.100, referenced in the Residential chapter cross‑references; see § 18.100.010 for applicability).
• Decoto Industrial Park Study Area (DIPSA): Chapter 18.102 contains the DIPSA rules (see § 18.102.010), with its own residential standards, access/road rules, and buffers to powerlines.

Overlay districts you will encounter (examples)

• Hillside Combining (-H): Chapter 18.96 (referenced in the residential cross‑lists) — applies additional slope/hillside specific requirements.
• Landmark and Historic Preservation (LHP): Chapter 18.106 — historic overlay controls.
• Housing Element (HE) overlay: Chapter 18.116 — used for housing policy implementation.

Quick reference table — most decision‑relevant districts and standards

Practical guidance / interpretation highlights

• Use the official zoning map first to identify the mapped district; the map is part of Title 18 and controls allowable uses for a parcel (map kept by City Clerk). If a zone boundary cuts a lot or is ambiguous, the ordinance provides rules for interpretation and empowers the Planning Commission to determine exact boundaries — verify lot‑specific boundaries with Planning staff. See the General Provisions chapter (Chapter 18.04).
• The code uses a letter matrix approach in district chapters: many uses are marked P (Permitted), AUP (Administrative Use Permit required), UP (Use Permit required), or “–” (not allowed). Check the district’s use table carefully; a use not listed is not permitted. See industrial and commercial tables (for example Table 18.40.020 and the C‑district tables in Chapter 18.36).
• For mixed‑use projects (including Union Landing and CMU/CMUE/SEE districts) expect both dimensional standards (FAR, minimum frontage, height) and qualitative performance criteria; site development review is a standard requirement (see § 18.76.010 and Union Landing chapters).
• Parking and loading are district‑specific: residential parking references § 18.32.160; commercial parking § 18.36.150; loading rules in § 18.36.140. Shared parking for mixed‑use ground‑floor commercial is evaluated on a case‑by‑case basis. Link: Union City Parking.
• Signs: every development is required to submit a Sign Plan (see § 18.30.100); blade and projecting sign allowances can be district‑ or area‑specific (Union Landing has additional allowances).

Checklist — what an applicant must satisfy (top items)

• Confirm the parcel’s official zoning district on the City’s official zoning map and note any overlays; the map is part of Title 18 (verify with City Clerk).
• Confirm whether your proposed use is listed as Permitted / AUP / UP in the district’s use table (see Chapter 18.36 for commercial, Table 18.40.020 for industrial, Chapter 18.32 for residential).
• Check dimensional standards (setbacks, height, FAR, lot coverage) in the district chapter and applicable tables (for CMUE/SEE see Table 18.41.060).
• Calculate parking and loading requirements per § 18.32.160 and § 18.36.150 / § 18.36.140 and prepare any shared‑parking justification if mixed‑use.
• Determine whether Administrative Site Development Review (§ 18.72.010) or Site Development Review (§ 18.76.010) applies; prepare plan sets and checklists accordingly.
• Prepare a Sign Plan if new signage is proposed (see § 18.30.100).
• Check overlays: Hillside (-H), LHP (historic), HE (Housing Element), 511 Area, DIPSA — any overlay or specific plan may modify base district rules (see Chapters 18.96, 18.106, 18.116, 18.100, 18.102).
• If proposing an ADU, consult Chapter 18.34 and state ADU law; ADUs are treated specially and are exempt from some Title 18 standards (Chapter 18.34). Link: Union City ADUs and California ADU law.

Risks & Ambiguities

Plain-English Summary

Union City’s Zoning Ordinance (Title 18) divides the City into named districts (residential RS/RM, commercial types CPA/CN/CC/CVR, industrial MG/ML/MS, special employment/mixed‑use districts such as CMUE/SEE, and area‑specific chapters like Union Landing and the 511 Area), each with its own permitted‑use table and dimensional standards; project approvals flow through administrative or Planning Commission review depending on the use and scale. Read the district chapter for permitted/conditional uses, check parking and loading sections, and expect site development review for most projects (see § 18.32.010, § 18.36.010, § 18.40.010, § 18.72.010, § 18.76.010).

Source References

• Title and purpose of the Zoning Ordinance: § 18.04.010.
• General provisions and official zoning map rules: Chapter 18.04 (map and boundary text visible in the file).
• Residential Districts: Chapter 18.32 (Residential districts purpose and standards; parking at § 18.32.160).
• Commercial Districts: Chapter 18.36 (use tables and related off‑street parking/loading rules at § 18.36.140 and § 18.36.150; outdoor dining § 18.36.190).
• Union Landing Commercial District: Chapter 18.39 (uses, development types, tables 18.39.040–050).
• Industrial Districts and use table: Chapter 18.40; Land Use Regulations Table 18.40.020; industrial performance restrictions. § 18.40.010.
• CMUE / SEE development standards table: Table 18.41.060 (development standards: FAR, frontage, setbacks, heights). § 18.41.060.
• Administrative Site Development Review: § 18.72.010 (Chapter 18.72).
• Site Development Review: § 18.76.010 (Chapter 18.76).
• Sign plan requirement: § 18.30.100 and sign chapter references.
• DIPSA: Chapter 18.102 (Decoto Industrial Park Study Area), § 18.102.010 – § 18.102.050.

Retrieved passages

• Union City Zoning Code (§ 4) High relevance show source text
• Union City Zoning Code (§ 2) High relevance show source text
• Union City Zoning Code (§ 5.6) High relevance show source text
• Union City Zoning Code (Title 18) High relevance show source text
• Union City Zoning Code (Chapter 18.40) High relevance show source text
• Union City Zoning Code (title may) High relevance show source text
• Union City Zoning Code (Chapter 18.30.) High relevance show source text
• Union City Zoning Code (Chapter 18.117) Medium relevance show source text

Cited sections

• Title and purpose of the Zoning Ordinance: **§ 18.04.010**. (Title and)
• General provisions and official zoning map rules: Chapter 18.04 (map and boundary text visible in the file). (Chapter 18.04)
• Residential Districts: Chapter 18.32 (Residential districts purpose and standards; parking at **§ 18.32.160**). (Chapter 18.32)
• Commercial Districts: Chapter 18.36 (use tables and related off‑street parking/loading rules at **§ 18.36.140** and **§ 18.36.150**; outdoor dining **§ 18.36.190**). (Chapter 18.36)
• Union Landing Commercial District: Chapter 18.39 (uses, development types, tables **18.39.040–050**). (Chapter 18.39)
• Industrial Districts and use table: Chapter 18.40; Land Use Regulations **Table 18.40.020**; industrial performance restrictions. **§ 18.40.010**. (Chapter 18.40)
• CMUE / SEE development standards table: **Table 18.41.060** (development standards: FAR, frontage, setbacks, heights). **§ 18.41.060**. (§ 18.41.060)
• Administrative Site Development Review: **§ 18.72.010** (Chapter 18.72). (§ 18.72.010)
• Site Development Review: **§ 18.76.010** (Chapter 18.76). (§ 18.76.010)
• Sign plan requirement: **§ 18.30.100** and sign chapter references. (§ 18.30.100)
• DIPSA: Chapter 18.102 (Decoto Industrial Park Study Area), **§ 18.102.010 – § 18.102.050**. (Chapter 18.102)
• UnionCity_ZoningCode.md

• Official Union City code library