Concord — Nonconforming Uses

Last reviewed: July 1, 2026

Overview

This page summarizes how Concord’s Development Code treats nonconforming uses, nonconforming structures, and nonconforming parcels (lots) under the local zoning code (Title 18). The city’s primary rules are in Chapter 18.530 (Nonconforming Uses, Structures, and Parcels) and Chapter 18.535 (Nonconforming Physical Improvements / Property Upgrades); those rules apply across the base zoning districts and overlays described below. See the controlling definitions in the code for how “nonconforming” is defined (§ 18.530.020 and related definitions). § 18.530.020 .

(Quick internal links used below: see parking, development standards, design review, overlay districts, ADUs, and the California Building Standards Code for related reviews.)

Citywide rules (what actually controls)

• Citywide definitions and applicability: § 18.530.020 defines nonconforming uses, nonconforming structures, and nonconforming parcels/lots and sets the baseline that only legally established uses/structures/parcels prior to the code change are eligible for nonconforming status. § 18.530.020 .

• Continuation, replacement and limits on intensification: Nonconforming uses may continue and may be replaced by similar or less-intensive nonconforming uses, but they may not be enlarged or intensified in ways that increase area, hours, employees, parking demand, noise, or traffic. See § 18.530.030(A). § 18.530.030 .

• Repair, improvement and expansion of nonconforming structures: Nonconforming structures may be repaired and in some cases enlarged provided the change does not increase the degree of nonconformity and any enlargement meets current code requirements; repairs and improvements are limited by a 50% value threshold in any 12‑month period for nonresidential/multifamily (with minor use permit relief when >50%). See § 18.530.030(B). § 18.530.030 .

• Loss of legal nonconforming status: Rights terminate if a use is discontinued for 365 consecutive days or more, or if a structure is involuntarily destroyed and the cost to repair/rebuild exceeds 50% of assessed value (different rules apply for residential rebuilding — see exemptions). See § 18.530.040. § 18.530.040 .

• Nonconforming parcels (legal building site): A parcel that doesn’t meet current lot area/width/depth may still be a legal building site if it was created by recorded subdivision or deed, or by variance or lot‑line adjustment, or small partial government acquisition conditions; subdivisions/lot line adjustments may not increase nonconformity nor be approved for parcels containing nonconforming uses. See § 18.530.050. § 18.530.050 .

• Nonresidential property upgrades: Chapter 18.535 requires prioritized upgrades (façade, trash/recycling enclosures, landscaping, signage, lighting, parking layout) when certain activities occur (new building, >25% expansion, re‑tenanting that increases parking demand, etc.). See § 18.535.030 and the Required Upgrades table. § 18.535.030 .

District-by-district breakdown

Below are the actual district names and the excerpted development standards that matter when you’re assessing whether a structure or use is nonconforming and what you may be able to do with it. Where the code gives a district-level table or overlay chapter, that citation is noted.

Important: the nonconforming rules themselves are citywide (Chapter 18.530) and apply to all base districts and overlays. The district entries below point to the district purpose and the key base standards you’ll compare an existing condition against when calculating nonconformity.

RR and RS (Rural Residential / Residential Suburban)

• Purpose: low-density residential, larger lots and rural character; see the RR/RS development standards table. Table 18.30.030 (RR and RS) lists min lot size, setbacks and similar development standards used to determine nonconformity. § 18.30.030 .
• Typical permitted uses: single-family dwellings, accessory uses consistent with low-density residential character (see Division II use tables).
• Key dimensional standards (examples from the table): minimum lot area and setbacks are district-specific in Table 18.30.030; these are the yard/depth metrics used to decide if a lot or building is nonconforming. See Table 18.30.030 § 18.30.030 .
• Where it applies: mapped out in Division II zoning maps (verify parcel zoning with the city).

How this matters for nonconforming treatment: an existing small lot or building in an RR or RS zone that predates a code change is a nonconforming lot/structure only if it was lawfully created; restoration after damage follows § 18.530 rules. § 18.530.020 and § 18.530.060(B) .

Office & Commercial districts — CO, CMX, NC, RC, SC

• Purpose: moderate- to higher-intensity commercial/office and mixed uses; see Table 18.40.030 for specific standards. § 18.40.030 .
• Typical permitted uses: offices, neighborhood commercial, retail, mixed residential uses in identified districts (see Division II use tables).
• Key dimensional standards (from Table 18.40.030): FAR up to 1.0 (CO, CMX), various minimum lot areas (e.g., 10,000 sf), building height ranges (residential/mixed use up to 37–40 ft, nonresidential 30–40 ft), and front setbacks often 10 ft / 5 ft / 5 ft depending on district. § 18.40.030 .
• Where it applies: downtown, commercial corridors and other mapped locations in Division II.

How this matters for nonconforming treatment: if an existing building exceeds today’s height or encroaches into today’s setbacks, it is a nonconforming structure and repairs/limited expansion are controlled by § 18.530.030(B). Chapter 18.535 may require property upgrades with alterations or tenant changes. § 18.530.030 and § 18.535.030 .

Business Park / Industrial districts — OBP, IBP, IMX, HI

• Purpose: business park and industrial uses. See Table 18.50.030 for standards (FAR, lot area, building height, setbacks). § 18.50.030 .
• Typical permitted uses: light industrial, warehousing, business park, research and development (use tables in Division II).
• Key standards: examples include FAR up to 1.0 in IMX, minimum lot area (10,000–40,000 sf depending on district), building heights to 50 ft in many industrial districts, and front setbacks 20–30 ft. § 18.50.030 .
• Where it applies: industrial parks and employment areas.

How this matters: nonconforming industrial buildings and site layouts (including outdated parking or loading configurations) are subject to the property upgrade requirements in Chapter 18.535 when you repave, build, add signage, expand >25%, or change use in a way that increases parking demand. § 18.535.030 .

Transit Station Overlay — TS

• Purpose: encourage higher density, pedestrian-oriented mixed use near BART stations. See Chapter 18.105 for purpose, applicability, prohibited uses and development standards. § 18.105.010–030 .
• Typical permitted uses: uses of the base district are allowed, subject to TS restrictions; certain uses (surface parking, recycling facilities, heavy maintenance) may be prohibited. § 18.105.030 .
• Key standards: TS may be combined with base districts within ½ mile of a BART station, and TS imposes pedestrian-oriented requirements and limits on incompatible uses. § 18.105.020–040 .
• Where it applies: lands within a ½ mile of BART stations (mapping in Division II).

How this matters: an existing use or building inside a TS overlay that becomes nonconforming at the time of annexation or code change is still treated under § 18.530, but redevelopment proposals must also satisfy TS development standards and pedestrian/parking rules. § 18.530.020 and § 18.105.020 .

Decision‑relevant quick reference table

Practical guidance & plain-English synthesis

• Prove legal origin: To claim nonconforming status you must show the use/structure/parcel was lawful under the rules that applied when it was established (not an illegal/unpermitted use). § 18.530.010–020 .

• Small repairs are allowed; big rebuilds are limited: Ordinary maintenance and repairs are allowed; but if you plan work that, in a 12‑month window, exceeds 50% of the building value for multifamily/nonresidential projects, expect a minor use permit and discretionary review. § 18.530.030(B) .

• If a nonconforming use goes dark for a year you lose the status: 365 days of documented inactivity will make the property subject to current zoning as if nonconforming rights never existed. Keep receipts, utility records, lease docs to show continuity. § 18.530.040(A) .

• For nonresidential sites, tenant changes and repaving commonly trigger required upgrades (façade repair, trash enclosures, landscape, signage, parking improvements). Budget those into renovation costs. § 18.535.030 .

• Overlays and district tables still apply: nonconforming status doesn’t exempt you from overlay rules (like TS) when you apply to rebuild or expand; you must meet overlay development standards or get appropriate approvals. § 18.105.020 and § 18.530.030 .

• Confirm building-code compliance separately: the nonconforming rules refer to reconstruction compliance with the building code; the city will require building permits and code compliance (see seismic and fire compliance allowances under § 18.530.030(B)(3)). For building-code provisions see the California Building Standards Code (Title 24). § 18.530.030(B)(3) .

Internal links for related topics you’ll likely consult while pursuing a project: see the Concord parking rules for parking triggers, Development Standards for dimensional checks, design review when aesthetic/major changes are proposed, overlay districts for overlay requirements, ADUs guidance when adding accessory units, and the California Building Standards Code for structural permit requirements.

Checklist (what an applicant must satisfy / bring to the Planning Division)

• Proof the use, structure, or parcel was lawfully established before the relevant code/amendment (recorded deed, previous building permit, business license, dated photographs, prior entitlements). § 18.530.020 .
• Site plan showing existing building footprints, previous area occupied by the use (to confirm no enlargement). § 18.530.030(A) .
• Cost estimates/contractor bids and building valuation (if doing repairs) to determine whether the 50% repair/alteration threshold is exceeded. § 18.530.030(B) .
• Evidence of continuous operation if asserting continued nonconforming use (business receipts, utility bills, lease continuation). § 18.530.040(A) .
• For nonresidential site changes: a property upgrades plan (façade, trash enclosure, landscaping, signage, parking) if triggers in § 18.535 apply. § 18.535.030 .
• If rebuilding after damage, documentation of damage valuation and timely filing of building permits (work must begin within 180 days and be prosecuted to completion as specified). § 18.530.040(B) .
• Zone verification and applicable district standards (use table, setbacks, FAR) from Division II to evaluate the degree of nonconformity. See district tables (e.g., § 18.40.030, § 18.50.030, § 18.30.030). .

Risks & Ambiguities

Plain‑English Summary

If a use, building, or lot in Concord was lawful when it was created but no longer complies with today's zoning, the code usually lets it keep operating—but you cannot expand its area or intensity, you can only make limited repairs (with a 50% annual repair/value cap for many nonresidential buildings), a year of inactivity will end your nonconforming rights, and certain tenant changes or rebuilds must bring the site up to current standards or trigger upgrades. See § 18.530 and § 18.535 for the full rules. § 18.530.020–070 and § 18.535.010–030 .

Source References

• Concord Development Code, Chapter 18.530 — Nonconforming Uses, Structures, and Parcels (purpose, applicability, continuation, loss of status) — § 18.530.010–070 .
• Concord Development Code, § 18.530.030 (continuation, limits on intensification, repair/50% rule, seismic/code compliance) — § 18.530.030 .
• Concord Development Code, § 18.530.040 (loss of nonconforming status — discontinuance and destruction rules) — § 18.530.040 .
• Concord Development Code, § 18.530.050 (Nonconforming parcels / legal building site criteria) — § 18.530.050 .
• Concord Development Code, Chapter 18.535 — Nonconforming Physical Improvements / Property Upgrades (triggers and upgrade priorities) — § 18.535.010–030 .
• Division II district tables (examples): Table 18.40.030 (Office & Commercial standards) and Table 18.50.030 (Business Park & Industrial standards) — § 18.40.030 and § 18.50.030 .
• Transit Station Overlay District (TS): Chapter 18.105 (purpose, applicability, land use regs) — § 18.105.010–030 .

Information Gaps

• Parcel-specific zoning details (exact base district for a parcel and its mapped overlays): Verify with the city zoning map (not in the retrieved files). Verify with the jurisdiction.
• Full text of every base district (e.g., specific R‑zone numeric setbacks for R‑1 or R‑2) was not present in the search snippets; the district tables included representative tables but not every R‑district row. Not found in retrieved materials — verify with the Division II district tables on the city site.
• Fee schedules and procedural timing for minor use permit (fee amounts, hearing timelines): Not found in retrieved materials — verify with the Planning Division fee schedule and Division VII procedures.

Retrieved passages

• Concord Zoning Code (§ 122-1316) High relevance show source text
• CFC § 530.030 (title shall) High relevance show source text
• Concord Zoning Code (§ 122-1319) High relevance show source text
• Concord Zoning Code (Chapter 18.530) High relevance show source text
• CFC § 122 (title shall) High relevance show source text
• CFC § 122 (§ 122-1318) High relevance show source text
• Concord Zoning Code High relevance show source text
• Concord Zoning Code (§ 122-248) High relevance show source text
• CFC § 122 (Chapter 18.505) High relevance show source text

Cited sections

• Concord Development Code, Chapter **18.530** — Nonconforming Uses, Structures, and Parcels (purpose, applicability, continuation, loss of status) — § 18.530.010–070 . (§ 18.530.010)
• Concord Development Code, **§ 18.530.030** (continuation, limits on intensification, repair/50% rule, seismic/code compliance) — § 18.530.030 . (§ 18.530.030)
• Concord Development Code, **§ 18.530.040** (loss of nonconforming status — discontinuance and destruction rules) — § 18.530.040 . (§ 18.530.040)
• Concord Development Code, **§ 18.530.050** (Nonconforming parcels / legal building site criteria) — § 18.530.050 . (§ 18.530.050)
• Concord Development Code, Chapter **18.535** — Nonconforming Physical Improvements / Property Upgrades (triggers and upgrade priorities) — § 18.535.010–030 . (§ 18.535.010)
• Division II district tables (examples): Table **18.40.030** (Office & Commercial standards) and Table **18.50.030** (Business Park & Industrial standards) — § 18.40.030 and § 18.50.030 . (§ 18.40.030)
• Transit Station Overlay District (TS): Chapter **18.105** (purpose, applicability, land use regs) — § 18.105.010–030 . (§ 18.105.010)
• Concord_ZoningCode.md
• 2025 California ADU handbook.md

• Official Concord code library