Local zoning · Rialto

Rialto — Nonconforming Uses

Nonconforming Uses under the Rialto local zoning and planning code, with the controlling citations.

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Last reviewed: July 2, 2026

Overview

This page explains how the City of Rialto treats nonconforming uses, nonconforming structures, and nonconforming lots under the local zoning code (Title 18). It sticks to the city's code language and practical interpretation: what may continue, what ends, rebuilding limits, special rules for residential zones, and a district-by-district snapshot of where these rules commonly appear. All legal requirements quoted below are grounded in the Rialto Municipal Code and cited to the controlling code sections. § references are shown where the code prescribes the rule.

How the rules fit together (short)

  • Definitions: nonconforming structure and nonconforming use are defined in § 18.04.600 and § 18.04.610.
  • The nonconforming-use chapter is Chapter 18.60 (rules that apply citywide). Key items: continuance rules, change-to-conforming, discontinuance, special R‑zone limits, sign/advertising amortization, and reconstruction after damage. See § 18.60.010–.120.

Citywide rules (what most property owners care about)

  • The nonconforming rules apply to existing buildings/structures/uses at the effective date of the zoning title and to uses/structures that later become nonconforming because of zone changes or ordinance amendments. See § 18.60.010.

  • Definitions you will use in every conversation with staff: "nonconforming structure" = a lawfully existing building that does not meet current district regulations; "nonconforming use" = a lawful use that does not comply with current district regulations. See § 18.04.600 and § 18.04.610.

  • Continued use vs. change:

    • A nonconforming building or structure may be maintained without physical change except for routine maintenance/repair, unless other chapters of the code allow changes. See § 18.60.020.
    • A nonconforming use may continue so long as it is not enlarged (no increase in area, space, or volume), except where the code provides otherwise. See § 18.60.030.
    • If a nonconforming part is changed to a conforming use, it may not later revert to a nonconforming use. See § 18.60.040.

  • Abandonment / discontinuance:

    • If a nonconforming use is discontinued for one year or more, it cannot be resumed as a nonconforming use. See § 18.60.050.

  • Changes among nonconforming uses:

    • If no structural alterations are made, a nonconforming use in a building may be changed to another nonconforming use of a more restrictive classification. See § 18.60.060.

  • Residential (R) zones — special amortization:

    • In all R zones, a nonconforming building or structure that was designed for a use not permitted in R zones must be removed or converted to a conforming use when it reaches 40 years old (the code delayed operation of this rule for 10 years from the title effective date; verify application dates for any given building). See § 18.60.070.
    • Also in R zones, any nonconforming land use (where no main building is involved) existing when the title became effective had to be discontinued within three years. See § 18.60.090.

  • Reconstruction after damage:

    • A nonconforming building partially damaged may be repaired/rebuilt and continued if reconstruction expense does not exceed 50% of the assessed value at time of damage; work must be started within one year of damage and completed under a single building permit. See § 18.60.110.

  • Nonconforming signs and special amortization:

    • Nonconforming signs could be continued but the code set removal deadlines for certain sign categories; consult § 18.60.100 and overlay-specific sign rules. See § 18.60.100.

  • Where other chapters override or add rules:

    • Some specific uses (e.g., dismantling facilities, outdoor storage, wireless facilities) have their own nonconforming rules layered on top of Chapter 18.60; those chapters reference Chapter 18.60 for continuance limitations. See Chapters 18.103, 18.104, and 18.111.

District-by-district breakdown

Below are the Rialto districts most commonly involved in nonconforming-use questions, with the code references and the specific standards that matter for nonconforming status.

A-1 (Agricultural) — A-1

  • Purpose / where it applies: agricultural activities on larger parcels. See § 18.08.010.
  • Typical permitted uses: farms, nurseries, poultry/rabbit raising, limited livestock, beekeeping, with separation distances and limits. See § 18.08.020 (A–F).
  • Key dimensional standards: lot area = 1 acre (43,560 sq. ft), lot width = 120 ft, building height/yard standards referenced to R-1A standards. See § 18.08.030.
  • Nonconforming notes: existing animal buildings that do not meet separation distances may continue as nonconforming uses subject to Chapter 18.60. See § 18.08.020(E) and § 18.60.010.

R zones (single‑family residential) — R‑1, R‑1A, other R zones

  • Purpose: preserve single‑family neighborhoods and apply residential development standards. See Chapter 18.10 (R‑1A referenced) and related R‑zone chapters. Not all R‑zone text is reproduced here; Chapter reference appears throughout Title 18. See § 18.10 references in the code and § 18.60.070–.090 for nonconforming rules.
  • Typical allowed uses: one‑family dwellings, accessory uses, ADUs (subject to code, see local ADU rules). See Chapter 18.10 and related sections.
  • Key nonconforming-statutory standards:
    • R‑zone buildings that were designed for a non‑residential use become subject to removal or conversion at age 40 years (subject to the code's effective-date timing). See § 18.60.070.
    • Nonconforming uses of land in R zones (no main building) were subject to a three‑year discontinuance requirement when the title became effective. See § 18.60.090.

M-1 / M-2 (Light and General Manufacturing) — M‑1, M‑2

  • Purpose / where it applies: light and general industrial uses, with a set of industrial standards and required buffers. See Chapter 18.42 and related M‑zone sections.
  • Typical permitted uses (examples): manufacturing, warehousing, indoor storage, limited accessory retail, subject to conditional permits for certain heavy activities; outdoor storage controlled by Chapter 18.104. See Chapter 18.42, Chapter 18.104.
  • Key dimensional/use-conditions: standards for buffering, noise, dust control, and setbacks when adjacent to residential; off-street parking per Chapter 18.58. See § 18.42.070, Chapter 18.61, and Chapter 18.58.
  • Nonconforming notes: specialty uses in M‑zones (for example, automobile dismantling facilities) have explicit nonconforming definitions and continuance rules in Chapter 18.103; those rules expressly reference Chapter 18.60 for limits on expansion and continuation. See § 18.103.050 and § 18.60.010.

Commercial zones — C‑2, C‑3, C‑M

  • Purpose: retail, service, freeway commercial and mixed commercial‑manufacturing applications. See Chapters 18.33–18.36 and chapters for C‑zones.
  • Typical permitted uses: retail shops, restaurants, professional offices, and conditionally permitted entertainment or automotive uses in specified locations. See C‑zone use lists in the applicable chapter.
  • Nonconforming notes: nonconforming signs and uses are handled by Chapter 18.60 and sign chapters (examples in § 18.60.100 and sign-specific sections). See § 18.60.100.

Specific plans & airport-related districts — Agua Mansa (M‑IND / H‑IND), Rialto Airport Specific Plan (I‑GM)

  • Purpose / where it applies: special design/performance standards tied to specific plans and the Rialto Airport. See the specific plan chapters and Chapter 18.50 (Airport Zoning).
  • Typical permitted uses: manufacturing, heavy industrial in Agua Mansa; airport‑compatible development in Airport SP. See specific plan text and Chapter 18.111 for wireless facility applicability.
  • Nonconforming notes: airport zoning has its own definition of nonconforming use/structure, and replacement or alteration of nonconforming structures in airport zones requires a permit from the planning commission so as not to increase airport hazards. See § 18.50.030–.080 and § 18.50.080 (replacement/alteration permit requirement).

Overlay / Corridor restrictions — Rialto Avenue–Cedar Avenue Corridor and Foothill Boulevard restrictions

  • Purpose / area: overlays limit how industrial/commercial properties convert and stipulate additional development, design, or amortization demands in corridor areas. See Chapter 18.43 for Rialto Avenue‑Cedar Ave overlay and Chapter 18.62 for Foothill Boulevard restrictions.
  • Specific to nonconforming property: Foothill Boulevard overlay explicitly defines structures placed within the planned right‑of‑way as nonconforming and sets a removal deadline (for physical obstructions within the planned ROW the code required removal no later than June 30, 2016 in the cited ordinance text). See § 18.62.020–.040.

Key standards & permitted-use summary (decision table)

Item / Question Rule or Typical Result (plain English) Code Reference
Definition: nonconforming structure Lawful building that doesn't meet current district regulations § 18.04.600
Definition: nonconforming use Lawful use that doesn't meet current district regulations § 18.04.610
Continuance of nonconforming building May be maintained; no physical change except maintenance/repair (unless other code allows) § 18.60.020
Continuance of nonconforming use May continue but no enlargement of area/space/volume § 18.60.030
Abandonment rule Discontinued for 1 year → may not resume as nonconforming § 18.60.050
R zones (nonresidential building age) Nonconforming building for nonresidential use must be removed/converted when 40 years old (with code timing caveat) § 18.60.070
R zones (nonconforming land uses) Nonconforming land uses (no building) — discontinue within 3 years (per code effective date) § 18.60.090
Reconstruction after damage Rebuild allowed if cost ≤ 50% of assessed value; start within 1 year; single permit § 18.60.110
Foothill ROW obstructions Nonconforming structures in planned ROW defined and subject to removal deadlines § 18.62.020–.040
Special-use chapters Dismantling, outdoor storage, wireless facilities have their own nonconforming rules referencing Chapter 18.60 Ch. 18.103, Ch. 18.104, Ch. 18.111

Practical checklist (what an applicant must satisfy)

  • Confirm whether the existing building/use was lawful when established and identify the date it became nonconforming. See § 18.04.600–.610.
  • Determine whether the proposed action is maintenance/repair (allowed) or an enlargement/alteration (may be prohibited). See § 18.60.020–.030.
  • If proposing structural repair after damage, prepare cost estimate vs. assessed value to prove rebuilding ≤ 50% (and plan to start within 1 year). See § 18.60.110.
  • If property is in an R zone, check whether the 40‑year conversion rule or the 3‑year discontinuance rule applies; collect construction date records. See § 18.60.070 and § 18.60.090.
  • If the property is in a special chapter (dismantling, outdoor storage, airport area), consult the specific chapter (e.g., 18.103, 18.104, 18.50) for additional limits and permit needs.
  • If you plan to change the use to a conforming use and later revert, be aware that once changed to conforming it may not be returned to nonconforming per § 18.60.040.
  • Check parking and site standards that may be triggered by any change (see the city's parking rules and development standards).

Risks & Ambiguities

Issue Why it matters What to verify
Age-based removal in R zones The 40‑year rule can force conversion or removal of buildings originally used commercially in R zones Verify original use/date of construction and whether the 10‑year delay to operation was applicable; consult § 18.60.070.
Whether a use was "lawful" when established Only lawful pre‑existing uses get nonconforming protection; illegal uses do not Check building permits, business licenses, and historical records; definitions in § 18.04.600–.610 and applicability § 18.60.010.
Reconstruction valuation threshold The 50% of assessed value test is often disputed (what counts as "assessed value" and "expense") Get assessor records and contractor estimates; verify compliance with § 18.60.110.
Overlay-specific removal deadlines (Foothill ROW) Some overlays set absolute removal dates (Foothill examples reference 2016) Confirm whether deadlines were enforced, extended, or superseded for the parcel; § 18.62.030–.040.
Conflicts with State ADU rules State ADU laws limit local conditioning based on nonconforming zoning conditions Local ADU-specific conflicts are not fully discussed in Chapter 18; check Rialto ADU policy and state law. Local code references ADUs in zone chapters; state guidance applies. Verify with staff. Not found in retrieved materials for local ADU procedure.

Plain-English Summary

If your Rialto property was legal when it was created but no longer meets today’s zoning rules, the city generally lets the use or building continue but limits enlargement, sets time limits for abandoned uses, and places special rules on residential areas (notably a 40‑year conversion rule and a 3‑year discontinuance rule for certain R‑zone uses). Rebuilding after damage is allowed only under a 50%‑of‑value threshold and other time limitations. All of these rules are in Chapter 18.60 and related chapter text; check the precise § cited for your situation.

Source References

  • Rialto Municipal Code — Chapter 18.60, Nonconforming Uses ( § 18.60.010–.120 ) —
  • Rialto Municipal Code — Definitions: § 18.04.600 (nonconforming structure) and § 18.04.610 (nonconforming use) —
  • Rialto Municipal Code — § 18.60.110 Reconstruction/repair after damage —
  • Rialto Municipal Code — Chapter 18.08 (A‑1 Agricultural zone; lot/use standards) —
  • Rialto Municipal Code — Chapter 18.42 (M‑2 General Manufacturing zone; use conditions) —
  • Rialto Municipal Code — Chapter 18.103 (Dismantling facilities; nonconforming rules) —
  • Rialto Municipal Code — Chapter 18.104 (Outdoor storage; applicability to nonconforming uses) —
  • Rialto Municipal Code — Chapter 18.50 (Airport Zoning — nonconforming definitions/permits) —
  • Rialto Municipal Code — Chapter 18.62 (Foothill Boulevard restrictions; nonconforming removal deadlines) —
  • Rialto municipal zoning overview: Rialto Zoning — use this portal to find the zone maps and chapter links (verify parcel zoning with the City).
  • Related city pages you may need during the process: Rialto Parking, Rialto Development Standards, Rialto Design Review, Rialto Overlay Districts, Rialto ADUs. (These pages are the correct internal links to consult for parking, setbacks, design review, overlays, and ADU interplay.)

If you want, I can: (a) map a single parcel to the specific zoning chapter language that controls nonconforming status, or (b) draft the exact information you need to bring to the Planning Department to prove a use was lawful and eligible for nonconforming protection. Verify parcel-specific facts with the City of Rialto.

Sources

Retrieved passages

  • Rialto Zoning Code (title shall) High relevance
  • Rialto Zoning Code (§ 1) High relevance
  • Rialto Zoning Code (chapter no) High relevance
  • Rialto Zoning Code (Title XII) High relevance
  • Rialto Zoning Code (§ 4) High relevance
  • Rialto Zoning Code (chapter apply) High relevance
  • Rialto Zoning Code (Title XII) High relevance
  • Rialto Zoning Code (chapter or) Medium relevance
  • Rialto Zoning Code (§ 66314) Medium relevance
  • CBC § 66314 (§ 66314) Medium relevance
  • Rialto Zoning Code (§ 66333) Medium relevance
  • Rialto Zoning Code (Chapter 18.104) Medium relevance
  • Rialto Zoning Code (title to) Medium relevance
  • Rialto Zoning Code (§ 1) Medium relevance
  • Rialto Zoning Code (Chapter 18.60) Medium relevance
  • Rialto Zoning Code (section 21064.3) Medium relevance
  • Rialto Zoning Code (§ 3) High relevance
  • Rialto Zoning Code (Section 11.04.230) Medium relevance
  • Rialto Zoning Code (§ 1) Medium relevance
  • Rialto Zoning Code (§ 1) Medium relevance
  • Rialto Zoning Code (Chapter 18.60) Medium relevance
  • Rialto Zoning Code (Section 220) Medium relevance
  • Rialto Zoning Code Medium relevance

Cited sections

Frequently asked questions

Can an existing nonconforming use expand in Rialto?

No — under Rialto's code a nonconforming use may be maintained but not enlarged (no increase in area, space, or volume) except where another part of the code allows it; see § 18.60.030.

What happens if a nonconforming business stops operating?

If the nonconforming use is discontinued for one year or more, it cannot be resumed as a nonconforming use. See § 18.60.050.

If my nonconforming building is damaged, can I rebuild it?

Yes — but only if reconstruction expense does not exceed 50% of the assessed value of the building at the time of damage; work must start within one year and be completed under a single permit. See § 18.60.110.

Do different Rialto districts treat nonconforming uses differently?

The city’s nonconforming chapter applies citywide, but R zones have special rules (e.g., 40‑year removal/conversion for certain nonresidential buildings and 3‑year discontinuance for uses of land), and some special chapters (airport, dismantling, outdoor storage) add additional requirements. Key rules are in § 18.60.070, § 18.60.090, and the special chapters (e.g., Ch. 18.103, Ch. 18.104).

Are signs treated the same as other nonconforming uses?

The code allows some lawfully existing signs to continue, but it also contains amortization/removal rules (see § 18.60.100) and sign‑specific chapters may impose deadlines or limits. See § 18.60.100.

Does an overlay (like Foothill Boulevard) change nonconforming treatment?

Yes. Overlays can create area‑specific nonconforming definitions and deadlines. For example, structures within the Foothill Boulevard planned right‑of‑way were defined as nonconforming and subject to removal no later than June 30, 2016 in the code's text; verify current enforcement/history with staff. See § 18.62.020–.040.

If a dismantling facility was lawful before a zoning change, can it continue?

Yes, an automobile dismantling facility that was lawful and continued operation may be treated as a legal nonconforming use but may not enlarge its area/volume; see § 18.103.050 and Chapter 18.60.

Who decides if a proposed new use is permitted in a zone?

A determination of use is handled by the planning commission; that process and appeal rights are in the code (see planning commission authority and determinations). See related administrative rules and Chapter 18.49 and the determination language in the code. Verify with staff for a site‑specific determination. Not every determination of use automatically must be granted. Not found in one single § in the retrieved materials; see the planning commission determination provisions and appeal chapters.

Can converting a nonconforming condition block an ADU permit?

Rialto’s Title references ADUs in zone chapters, but state ADU law limits local ability to condition ADU permits on fixing nonconforming zoning conditions. Local practice should be verified with the City’s ADU process and the Rialto ADU page. Local ordinance text addressing ADU/nonconformance was not reproduced in the retrieved materials. Verify with the City. Not found in retrieved materials (local ADU-specific guidance).

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