Local zoning · San Marino

San Marino — Nonconforming Uses

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

Last reviewed: July 2, 2026

Overview

This page summarizes what the City of San Marino zoning code says about nonconforming uses, nonconforming buildings/structures, and nonconforming lots — the rules that govern whether an existing use or structure that does not meet today's zoning rules can remain, be changed, or must be brought into compliance. It draws directly on the Zoning Code (Chapter XXIII) provisions that treat abandonment, enlargement, repairs after damage, and special rules for residential zones such as R-1. See the city's zoning summary for context on the code and maps at San Marino Zoning & planning overview and San Marino Zoning.

Note: This page stays strictly within the local zoning / planning ordinance. For building-code (Title 24), permitting, or housing-law implications see the linked pages (for example, the California Building Standards Code and ADU law links below).

Core Zoning Rules for Nonconforming Uses (plain-English synthesis)

A lawful use or building that existed on the effective dates identified in the code may be continued even if it no longer complies with current zoning, but the scope for that continuation is explicitly limited by the ordinance. See § 23.06.08 for the primary rules about existing nonconforming uses.
Abandonment deadlines: If a nonconforming condition exists solely because of missing off‑street parking and the use is abandoned, the owner has 12 consecutive months before it can be re-established without meeting parking requirements or securing a conditional use permit; for other nonconformances, abandonment for 6 months removes the right to resume the nonconforming use. § 23.06.08
Enlargement and alteration: Nonconforming uses and buildings generally may not be structurally enlarged or extended except to bring them into conformity; limited exceptions exist (for example, some expansions tied to providing added parking for restaurants). § 23.06.08
Repair after damage: A building damaged more than 50% of its replacement value cannot be rebuilt except in conformity with the current code; there is a specific exception for legal nonconforming residential or accessory buildings damaged by fire or earthquake (they may be rebuilt on prior foundations/footprints). § 23.06.11
Minimum-lot protections: The code protects the ability to build or expand a single-family dwelling on an older, pre‑existing lot that became substandard by later changes, provided the lot met certain recording/creation tests prior to the stated date. § 23.06.12

Practical takeaway: nonconformities are tolerated but tightly circumscribed — abandonment, >50% destruction, or unauthorized enlargement are the common triggers that terminate nonconforming rights. Always confirm the critical dates and whether the use was lawful on those dates.

District-by-district treatment (what the code says about nonconforming situations per zone)

Note: The zoning code is organized by Articles and Area Districts within the R-1 zone; many nonconforming rules are general (Article 06 nonconforming rules) and applied across zones. Where the code gives zone-specific rules they are shown below with the controlling code citations.

R-1 (Single-Family Dwelling Zone)

Purpose / where it applies: The R-1 zone regulates single-family residential areas and subdivides them into Area Districts IE, I, II, III, IV, V, VI, VII with different lot-size and yard requirements. See the R-1 development table in § 23.02.09 for the area-district matrix.
Typical permitted uses: Single-family dwellings and accessory residential uses; commercial uses are generally not authorized in R-1 (commercial uses on R-1 sites are subject to the C-1 development standards and are not authorized as new uses). § 23.06.02
Key dimensional standards that matter for nonconformance (examples):
- Minimum front yard varies by area district (e.g., 40 ft in districts IE and I, 40 ft in II/III, decreasing to 25–30 ft in smaller districts) — see the full R-1 yard table in § 23.02.09. § 23.02.09
- Lot coverage and livable area caps follow area-district percentages — see § 23.02.10 for maximum lot coverage by area district (e.g., 30%–40% depending on district). § 23.02.10
- For an existing primary structure with a legal nonconforming side yard, the ordinance treats the existing side yard setback as the required setback for any single‑story addition on that side (subject to a minimum 5 ft distance); if the existing setback is less than 5 ft, a conditional use permit is required. § 23.06.04 (E)
Nonconforming-specific rules:
- Additions that increase lot coverage by more than 20% must comply with the R-1 compliance requirements referenced in the code (conditional use relief exists but has a process). § 23.02.?? (R-1 compliance subsection referenced in code excerpt) Not found in retrieved materials — the code text referencing the R-1 compliance process appears in the file but the precise subsection title/number for the “Requirement for Compliance” language is present in the file excerpts; verify with the jurisdiction.
- Garages built before certain dates are treated as conforming if they meet the size definitions, and accessory building rebuilding/changes are tightly regulated (see the garage rules and accessory building setbacks in § 23.02.23). § 23.02.23
Where to check on your parcel: confirm your Area District (IE–VII) on the yard map and the R-1 table in § 23.02.09; verify whether an existing setback or lot dimension was “lawful” on the relevant historical date. § 23.02.09, § 23.06.12

(See the city’s Development Standards for how these numbers integrate with other rules.) San Marino Development Standards

C-1 (Neighborhood Commercial Zone)

Purpose / where it applies: C-1 covers neighborhood commercial strips (e.g., Huntington Drive, Mission Street), with a set of allowed retail and service uses and specific development standards. § 23.03.01
Typical permitted uses: banks, retail, markets, small restaurants, professional offices, some services; a long list of excluded/prohibited uses is also specified. § 23.03.01
Nonconforming-specific rules:
- Certain lawfully preexisting uses that are now classified as conditional uses are not automatically treated as nonconforming simply because a procedural conditional-use requirement now applies — but the code creates a process by which the Commission can declare abandonment/nonconformance after notice and discontinuance (see § 23.06.09). § 23.06.09
- Nonconforming parking shortfalls are treated strictly: if a use is nonconforming solely due to parking and is abandoned > 12 months, additional parking and a CUP are required to re-establish the use. § 23.06.08
Special commercial-to-residential notes: the code treats restaurant expansions and some professional office changes with distinct off‑street parking rules where a building is legal nonconforming for parking — see the use list and special provisions in § 23.03.01 and cross-references in § 23.06.08. § 23.03.01, § 23.06.08

(If your project proposes to rely on an off‑site parking plan for a nonconforming parking condition, consult the code’s off‑site plan criteria.) San Marino Parking

RM1, RIH, MU-1, MU-2, H&C (Multi-family / mixed-use zones)

Purpose / where it applies: These zones regulate various multifamily and mixed‑use forms; the code contains a uses table and development standards for these zones (see Article 20 / Article 05). § 23.20.02 details permitted uses for RM1 and RIH.
Nonconforming-specific rules:
- The general nonconforming rules in § 23.06.08–11 apply citywide (abandonment timelines, enlargement prohibition, repair-after-damage >50% rule). § 23.06.08–23.06.11
- For certain housing and shelter uses added by recent ordinances, the code establishes objective standards and by-right procedures (Article 23 By-Right Approval) that interact with nonconforming-use questions; consult § 23.23.01–05 for by‑right eligibility. § 23.23.01–.05

Historic and overlay treatments (where they intersect nonconformity)

Historic resources and overlay districts may impose additional constraints or provide special treatment for existing buildings; see the Historic Preservation article and the Overlay Districts article. The zoning code treats historic and design-control overlays as part of site‑specific regulation; check the Historic Preservation article when evaluating a nonconforming historic property. § 23.18.01, and overlays referenced throughout the code. § 23.18.01

For policy-level interactions with design controls, see San Marino Design Review and San Marino Overlay Districts. San Marino Design Review San Marino Overlay Districts

Decision-relevant quick reference table (selected standards)

Issue / Standard	What the Code Says	Code Reference
Abandonment — parking-only nonconformance	If nonconforming solely for parking, abandonment > 12 months prevents reestablishment without added parking and a CUP	§ 23.06.08
Abandonment — other nonconformance	If nonconforming for reasons other than parking, abandonment > 6 months ends right to resume; only conforming uses allowed thereafter	§ 23.06.08
Enlargement/structural alteration of nonconforming building	Not permitted unless bringing into conformity; limited exceptions for restaurants with added parking; side-yard-based additions permitted under narrow conditions	§ 23.06.08
Repair/rebuild after damage	If damaged > 50% of replacement value, must be rebuilt in conformity (residential/accessory exception exists)	§ 23.06.11
R-1 area district yard & lot table (examples)	Front yard and side/rear yard minima vary by Area District (see table; e.g., Front yard 40 ft in Area Districts IE/I)	§ 23.02.09
Maximum lot coverage by area district	Lot coverage caps range 30%–40% by area district; see table in code for exact percent per district	§ 23.02.10
Existing fences/hedges	Preexisting fences/hedges that violate current rules are treated as existing nonconforming structures and are subject to nonconforming rules (replacement limited if >50% destroyed)	(fence provision referencing nonconforming rules) § 23.06.08

Checklist (what an applicant must confirm or bring to the planner)

Document that the use/structure was lawful and existed on the code’s relevant effective date (for uses, the code uses August 8, 1953 as a baseline for “existing” in the nonconforming-use article). § 23.06.08
Confirm whether the nonconformance is parking‑only (different abandonment rule) and gather historical parking records if needed. § 23.06.08
Measure damage/replacement costs if rebuilding after destruction to determine whether the 50% threshold applies. § 23.06.11
If planning addition/remodel, verify whether the work would enlarge a nonconforming use or structure (generally prohibited) or would qualify as a permitted side‑yard single‑story addition under the R‑1 rules. § 23.06.08, § 23.06.04(E)
If relying on a nonconforming parking situation, prepare a parking plan and be ready to apply for a conditional use permit if abandonment has elapsed or expansion requires added parking. § 23.06.08
Look up your Area District (IE–VII) and confirm numeric setback/coverage limits in § 23.02.09 and § 23.02.10; bring a yard/lot diagram to the pre‑application meeting. § 23.02.09, § 23.02.10
If the property is in a historic district or overlay, confirm additional design review or preservation rules. § 23.18.01

Risks & Ambiguities

Issue	Why it matters	What to verify
Whether a use was “lawful” and in existence on the ordinance cutoff date	The right to continue as nonconforming hinges on historical lawfulness; missing proof can force immediate loss of nonconforming status	Verify recorded permits, business licenses, historical photos, dated utility bills; confirm with City records. § 23.06.08
Parking-only nonconformance vs. other nonconformance	Parking-only nonconformance gets a longer abandonment window (12 months) and specific remedy requirements	Confirm whether the only deficiency is parking; if yes, prepare to provide additional parking or CUP if reestablishing after 12 months. § 23.06.08
>50% destruction threshold	If damage exceeds 50% of replacement value, rebuilding may require full compliance with current code (which can eliminate nonconforming rights)	Obtain a damage/replacement-value appraisal and consult planning staff before repair/demolition. § 23.06.11
“Existing” designations for accessory structures (garages, fences, hedges)	The code has date‑based cutoffs and different rules for fences, hedges, and pre‑1997 garages — replacement and enlargement are limited	Check the specific historical date and whether the structure meets the code’s historic‑construction tests; if uncertain, “Verify with the jurisdiction.” § 23.02. (fence/garage provisions) / § 23.06.08*
Parcel‑specific yard map vs. area-district table	Some lots have unique “yard map” delineations that supersede table minima	Review the yard map entry for the parcel; where conflict exists the yard map dimension controls. § 23.02.09

Plain-English Summary

If your San Marino property or business was lawful when the zoning code (or a later amendment) took effect, you can usually keep that use or structure — but the city will stop you from enlarging it, rebuilding it after major damage, or resuming it after extended abandonment; parking shortfalls, >50% destruction, or abandonment timelines are the most common ways nonconforming rights are lost. § 23.06.08–23.06.11

Information Gaps (what the retrieved materials did not establish)

Exact cross-references and subsection numbers for the R-1 “Requirement for Compliance” language were present in the file excerpts but the snippet did not show a single clean subsection number for every R-1 compliance trigger — Verify with the jurisdiction. Not found in retrieved materials.
If the property is subject to a site- or parcel-level overlay (historic, yard-map exceptions), the code text in the excerpts indicates interactions but does not list parcel-by-parcel outcomes — Verify with the jurisdiction and the yard map. Not found in retrieved materials.
Administrative procedures (forms, fees, historic review timelines, evidence standards to prove continuity) are not in the zoning text excerpts provided — those are administrative details that must be confirmed with the Planning Department. Not found in retrieved materials.

Source References

Zoning Code — Nonconforming Uses: § 23.06.08 (Existing Nonconforming Uses)
Zoning Code — Existing Nonconforming Conditional Uses: § 23.06.09
Zoning Code — Nonconforming Buildings & Repair after Damage: § 23.06.10, § 23.06.11
R-1 yard and area-district table: § 23.02.09
Lot coverage and livable-area percentages: § 23.02.10
Garage/accessory structure rules (setbacks; pre‑1997 garage treatment): § 23.02.23 and related accessory-building provisions
C-1 permitted uses and special provisions (commercial nonconforming context): § 23.03.01
Fences/yards nonconforming-structure guidance (existing fences and hedges referenced to the nonconforming article): local fence subsection (existing-nonconforming structures) and cross-reference to § 23.06.08
By-right approvals and recent housing-related changes (interaction with nonconforming uses for certain housing projects): § 23.23.01–.05

Internal guidance pages referenced (for related topics mentioned above):

San Marino Zoning & planning overview: /us/california/san-marino
San Marino Zoning: /us/california/san-marino/zoning
San Marino Development Standards: /us/california/san-marino/development-standards
San Marino Parking: /us/california/san-marino/parking
San Marino Design Review: /us/california/san-marino/design-review
San Marino Overlay Districts: /us/california/san-marino/overlay-districts
San Marino ADUs: /us/california/san-marino/adu
California Building Standards Code (Title 24): /us/california/building-codes

Sources

Retrieved passages

San Marino Zoning Code (chapter and) High relevance
San Marino Zoning Code (chapter pertaining) High relevance
San Marino Zoning Code (section 23.06.08) High relevance
San Marino Zoning Code (section may) High relevance
San Marino Zoning Code (Section are) High relevance
San Marino Zoning Code (ARTICLE 23) Medium relevance
San Marino Zoning Code (article 03) Medium relevance
San Marino Zoning Code (article 07) Medium relevance
San Marino Zoning Code Medium relevance
San Marino Zoning Code Medium relevance
San Marino Zoning Code (section shall) Medium relevance
San Marino Zoning Code (§ 65913.4) Medium relevance

Cited sections

Official San Marino code library

Frequently asked questions

What triggers loss of a nonconforming use in San Marino?

The zoning code treats abandonment and substantial damage as the main triggers: a use abandoned for 6 months (or 12 months if the only nonconformance is parking) generally loses its nonconforming status; buildings damaged more than 50% of replacement value must be rebuilt to current code, which may extinguish nonconforming rights. § 23.06.08, § 23.06.11

Can I enlarge a building that is a legal nonconforming use?

No — the code generally prohibits structural additions or enlargements to a building used for a nonconforming use, except when the work brings the building into conformity or in narrowly described exceptions (for instance certain restaurant expansions if additional parking is provided). § 23.06.08

If my business lacks required parking, how long before I lose the right to operate?

If the nonconforming condition is solely a failure to meet off‑street parking requirements and the use is abandoned for 12 consecutive months, it cannot be re-established without providing additional parking and obtaining a conditional use permit. § 23.06.08

Are preexisting fences and hedges treated as nonconforming?

Yes — fences, gates, yard walls, and hedges installed prior to the code’s specified dates are classified as existing nonconforming structures and are subject to the nonconforming‑use rules (including limited replacement where >50% destroyed). Check the fence/wall provision that cross‑references the nonconforming article. (fence provision; cross-reference to § 23.06.08)

If my house is on a lot made substandard by later zoning changes, can I still build/expand?

Yes — the code protects lots that were separately shown or deeded prior to the ordinance cutoff (see the recorded‑map/deed/contract tests). A single‑family dwelling can be built/expanded on such lots but must comply with the development standards in effect at the time of construction/expansion. § 23.06.12

What happens if a legal nonconforming residential accessory building is damaged in an earthquake?

Residential and accessory buildings that are legal nonconforming and are damaged by fire or earthquake may be rebuilt on their prior foundations/footprints in many cases; however, if a building is more than 50% destroyed, the general >50% rule to rebuild to current code applies unless the residential accessory exception applies. § 23.06.11

Do I need a conditional use permit (CUP) to change a preexisting conditional use that became nonconforming?

The code states that uses now listed as conditional that were previously lawfully in existence are not automatically nonconforming solely because of the new procedural requirement; but if the preexisting conditional use has been discontinued after notice the Planning Commission may commence proceedings to declare it nonconforming and abate it. Prepare for a CUP if the use has been abandoned or you plan an expansion that changes parking or other conditions. § 23.06.09, § 23.06.08

How do R‑1 “Area Districts” affect nonconforming yard/setback issues?

R‑1 rules are area‑district specific (IE to VII). The yard/lot minima and maximum lot coverage vary by district (see the table in § 23.02.09 and coverage caps in § 23.02.10). For a primary structure with a legal nonconforming side yard, the existing side yard is used to determine setbacks for a single‑story addition provided certain minimums (generally 5 ft) are met or a CUP is obtained if less. § 23.02.09, § 23.02.10, § 23.06.04(E)

Can an ADU be denied because of nonconforming zoning conditions on my property?

State ADU law limits denial for correction of nonconforming zoning conditions; San Marino’s ordinance must be applied consistent with state law — consult the San Marino ADU rules and state ADU statutes. The zoning code’s nonconforming rules still apply to the underlying property but local ADU provisions interact with these principles. See San Marino ADUs and the California Building Standards Code for building requirements. San Marino ADUs California Building Standards Code ---

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