San Marino — Historic Preservation

Last reviewed: July 2, 2026

Overview

This page summarizes what the City of San Marino's zoning code requires for identification, designation, alteration, and incentives for historic landmarks and historic resources. The rules are codified in the Zoning Code’s Historic Preservation article (Article 18, 23.18) and tie into design review, ministerial development standards, and building-permit procedures (including the State Historical Building Code). Key local tools are designation (Council resolution), a required Certificate of Appropriateness, maintenance obligations, and preservation incentives (Mills Act, fee relief). See the city's zoning primer for context on districts and process at San Marino Zoning.

How San Marino’s Historic Preservation rules work (core rules)

• Designation: The City Council is the only body that may formally designate a historic landmark; nationally or state‑listed properties are automatically local landmarks. See § 23.18.03.
• Work controls: Any alteration, restoration, relocation, or demolition of a designated historic landmark requires a Certificate of Appropriateness (or a Certificate of Economic Hardship) before work may begin — § 23.18.07 and § 23.18.08.
• Review routing: The Planning & Building Director may approve minor work; larger or non‑eligible cases go to the Planning Commission (the ordinance defines Director vs. Commission thresholds, e.g., repairs vs. additions over 150 sq ft). See § 23.18.08(B–C).
• Findings: Certificates require findings including consistency with the Secretary of the Interior’s Standards and no substantial adverse CEQA change to the resource’s significance (§ 23.18.08(D)).
• Maintenance: Owners must keep designated properties in good repair; failure to maintain is not a valid basis for demolition approval (§ 23.18.06).
• Demolition: Demolition generally is prohibited unless a replacement permit is in hand or unsafe conditions justify it under § 23.18.14; additional findings apply to demolition requests (§ 23.18.08(D)(2)).
• Incentives: The City can offer Mills Act contracts, fee relief (including a 50% building‑permit fee refund for Secretary’s Standards‑compliant projects), SHBC facilitation, and preservation easements (§ 23.18.17).

Practical note: preservation review is a separate prerequisite to building permits for designated resources — plan review and design materials required can be substantial. See the city's design review standards for documentation expectations.

District-by-district breakdown (what the ordinance says about each zone relevant to historic preservation)

The zoning code names its districts in § 23.01.05; the code’s Historic Preservation provisions apply to historic landmarks and resources citywide regardless of zone, but some zone rules intersect with preservation review (for example, ADUs in historic properties or front-yard rules in single‑family zones).

R-1 (Single‑Family Dwelling Zone)

• Purpose: Standard single‑family district established by the Zoning Code; the Historic Preservation article applies to designated resources within it. § 23.01.05.
• Typical uses: Single‑family residences (and accessory uses governed elsewhere). Noted R‑1 rules on front‑yard landscaping and impervious surfaces can trigger design review when thresholds are exceeded. § 23.02 (front‑yard/impervious rules).
• Key standards that commonly intersect with preservation: front‑yard impervious coverage limited to 45%; recreational courts in R‑1 require a conditional use permit and building permit; if front‑yard impervious coverage is ≥ 25% the lot may be subject to design review. See § 23.02 and § 23.02.05.
• Where it applies: citywide neighborhoods shown on the zone map; if a structure in an R-1 zone is designated historic, the COA process controls exterior changes. § 23.01.05 and § 23.18.

C-1 (Commercial Zone)

• Purpose: Local commercial district; the code provides zone standards that can affect permitted work on commercial historic resources. § 23.01.05.
• Typical uses: Retail/restaurant/office uses (see the C‑1 article for use lists). The C‑1 zone has a 30 ft height limit that applies to new construction. § 23.03.02.
• Preservation intersection: Any designated historic property in C‑1 still requires a COA for exterior work; design expectations reference Secretary’s Standards. § 23.18.07–08.

H&C (Historical & Cultural Zone)

• Purpose & typical uses: The code lists a H&C zone in the list of zones; however, specific H&C development standards and permitted uses are Not found in retrieved materials beyond its existence in the zone list. § 23.01.05.
• Preservation intersection: Use of a designated H&C zone suggests added local emphasis on preservation, but specific H&C rules were not located in the retrieved excerpts. Verify with the City for the H&C zone text and map. Verify with the jurisdiction. Not found in retrieved materials.

RM1 (Multi‑Family Residential Zone), MU‑1 / MU‑2 (Mixed‑Use Zones), RIH (Religious Institution Housing), P&R (Park & Rec)

• Purpose & uses: These zone names appear in the zone list § 23.01.05. The Historic Preservation article applies if a resource in these zones is designated. Specific dimensional or permitted‑use rules for each zone were not detailed in the retrieved material for preservation‑specific intersections. Not found in retrieved materials for preservation‑specific standards in those zones. Verify with the jurisdiction.

Note: wherever the Historic Preservation article refers to certificate procedures, director/commission review, appeals, incentives, or the SHBC, those rules apply across zones to properties meeting the historic definitions in § 23.18.02–03.

Most decision‑relevant standards and permitted‑use table

Checklist — what an applicant must satisfy (preservation‑related)

• Confirm whether the property is a designated historic landmark or listed on the National/State register; automatic designation rules apply. § 23.18.03.
• If designated, prepare a Certificate of Appropriateness application (forms to Planning & Building) with: description of work, compatibility statement with the Secretary’s Standards, scaled plans, elevations, materials/colors, site plan, photos, and fees. § 23.18.08(A).
• Determine review route (Director vs Commission). If work is minor (repair in kind or rear ≤ 150 sq ft addition not visible from right‑of‑way) Director review may be possible; otherwise expect Commission hearing. § 23.18.08(B–C).
• For demolition requests, assemble the special findings and, if needed, economic hardship documentation (detailed financials, appraisals, rehabilitation estimates). § 23.18.08(D)(2) and § 23.18.09.
• If pursuing incentives (Mills Act or fee relief), verify eligibility and prepare the program submittal; fee refund eligibility requires compliance with Secretary’s Standards. § 23.18.17.
• Coordinate with design‑review documentation requirements (eight sets, full elevations, landscape, etc.) as applicable. See design review documentation requirements.
• If the project involves building‑code issues for historic work, the State Historical Building Code / Title 24 may be used; consult building staff. § 23.18.17(C).

Risks & Ambiguities

Plain‑English Summary

If your San Marino property is (or becomes) a historic landmark, you cannot change, demolish, move, or add to it without a Certificate of Appropriateness (or proving economic hardship); the Planning Director handles minor fixes but larger changes go to the Planning Commission and the City Council controls designation. The rules require work to follow the Secretary of the Interior’s Standards, allow Mills Act and fee relief incentives, and permit use of the State Historical Building Code for rehabilitation. § 23.18 contains the full process and standards.

Source References

• San Marino Zoning Code — Article 18, Historic Preservation: § 23.18.01–23.18.18 (purpose, definitions, designation, COA, economic hardship, maintenance, unsafe conditions, incentives, enforcement).
• Certificate of Appropriateness procedures and Director v. Commission review: § 23.18.07–08.
• Designation criteria for historic landmarks: § 23.18.04.
• Maintenance requirements and enforcement: § 23.18.06.
• Unsafety/unsafe conditions and demolition constraints: § 23.18.14.
• Preservation incentives (Mills Act, SHBC, fee relief): § 23.18.17.
• Zone list (names including R‑1, C‑1, H&C, RM1, MU‑1/2, etc.): § 23.01.05.
• R‑1 front yard / impervious coverage and recreational court rules: § 23.02 / § 23.02.05.
• C‑1 building height (example of zone standard): § 23.03.02 (maximum 30 ft).
• Design review documentation requirements referenced by preservation review: § 23.15.13.
• ADU rules referencing historic resources (ADU standards & exemptions): ADU provisions in the zoning code (ADU article) — retrieved ADU excerpt: ADU standards for historic properties (no section number in snippet; see ADU article).
• State Historical Building Code (context for building‑code treatment of historic work) — California SHBC guidance in the files.

Retrieved passages

• San Marino Zoning Code (section 23.18.14) High relevance show source text
• San Marino Zoning Code (section 23.18.14) High relevance show source text
• San Marino Zoning Code (section 23.18.04) High relevance show source text
• San Marino Zoning Code (section or) High relevance show source text
• San Marino Zoning Code High relevance show source text
• San Marino Zoning Code (article shall) High relevance show source text
• CBC § 18950 (section 18950) High relevance show source text
• San Marino Zoning Code (article shall) High relevance show source text
• CBC § 18950 (section 18950) High relevance show source text
• CBC § 50280 (article to) High relevance show source text
• San Marino Zoning Code (chapter VIII) High relevance show source text

Cited sections

• San Marino Zoning Code — Article 18, Historic Preservation: **§ 23.18.01–23.18.18** (purpose, definitions, designation, COA, economic hardship, maintenance, unsafe conditions, incentives, enforcement). (Article 18)
• Certificate of Appropriateness procedures and Director v. Commission review: **§ 23.18.07–08**. (§ 23.18.07)
• Designation criteria for historic landmarks: **§ 23.18.04**. (§ 23.18.04)
• Maintenance requirements and enforcement: **§ 23.18.06**. (§ 23.18.06)
• Unsafety/unsafe conditions and demolition constraints: **§ 23.18.14**. (§ 23.18.14)
• Preservation incentives (Mills Act, SHBC, fee relief): **§ 23.18.17**. (§ 23.18.17)
• Zone list (names including **R‑1**, **C‑1**, **H&C**, **RM1**, **MU‑1/2**, etc.): **§ 23.01.05**. (§ 23.01.05)
• R‑1 front yard / impervious coverage and recreational court rules: **§ 23.02 / § 23.02.05**. (§ 23.02)
• C‑1 building height (example of zone standard): **§ 23.03.02** (maximum **30 ft**). (§ 23.03.02)
• Design review documentation requirements referenced by preservation review: **§ 23.15.13**. (§ 23.15.13)
• ADU rules referencing historic resources (ADU standards & exemptions): ADU provisions in the zoning code (ADU article) — retrieved ADU excerpt: ADU standards for historic properties (no section number in snippet; see ADU article). (section number)
• State Historical Building Code (context for building‑code treatment of historic work) — California SHBC guidance in the files.
• SanMarino_ZoningCode.md
• 2025 California Historical Building Code.md

• Official San Marino code library