Signal Hill — Historic Preservation

Last reviewed: July 2, 2026

Overview

Signal Hill’s zoning code treats historic preservation mostly through a dedicated specific plan for the Crescent Heights historic neighborhood, through general tools that allow design-control and covenant/easement restrictions to protect historic resources, and by limiting certain ministerial housing approvals on parcels that are historic or inside an adopted historic district. The controlling local provisions are concentrated in the SP‑11 Crescent Heights Historic District Specific Plan and in several chapters that require site plan and design review or permit modifications to protect historic resources. See the city's site‑level rules for design review, parking, development standards, overlays and ADU policy when you prepare an application. § 20.31.010–.035, § 20.52.010–.020, and § 20.18.140 are the primary local code hooks.

How Signal Hill’s code handles preservation (high‑level)

• The City adopted a stand‑alone historic district specific plan, SP‑11 (Crescent Heights Historic District Specific Plan); the specific plan replaces ordinary zoning/development standards inside the district and provides tailored guidelines for relocating, modifying, or constructing homes compatible with the district’s historic character. § 20.31.010–.020.

• The city’s normal review vehicle for compatibility and exterior changes is site plan and design review: nearly all projects that change building massing, facades, or site layout require review under § 20.52.010–.020. That review is where preservation‑sensitive design choices (materials, massing, mechanical screening, storefront treatment) are evaluated.

• The code explicitly allows the planning decisionmakers to modify development standards in exchange for permanent preservation restrictions (easements/covenants) where the restriction protects “historic or cultural value” or provides a façade easement; those modifications are subject to the findings in § 20.18.140. Use this when an applicant wants deviations tied to protecting a historic resource.

• Some ministerial housing allowances (e.g., two‑unit projects) are barred on parcels that are historic or inside an adopted historic district; see § 20.10.041(E)(4). That creates a practical interaction between housing ministerial entitlements and preservation.

Note: This page stays within the local zoning/planning ordinance — seismic, life‑safety, or Title 24 building‑code exceptions are handled by building/safety (see California Building Standards Code). Signal Hill Design Review California Building Standards Code

District‑by‑district breakdown

SP‑11 — Crescent Heights Historic District Specific Plan

• Purpose: The SP‑11 district is a defined historic district intended to “guide the orderly development” of the Crescent Heights area and to implement historic preservation goals, including relocating and modifying historically significant dwellings and ensuring new construction is compatible with the district character. § 20.31.010 and § 20.31.020.

• Typical permitted uses: Residential uses consistent with the Specific Plan; the code also explicitly allows certain special‑needs housing as “by right” per state law inside SP‑11. § 20.31.025.

• Key dimensional / design standards (decision‑relevant examples):

  • Front‑setback hardscape cap: the maximum hardscape within the front setback is limited to 25% of the setback area (driveway allowance excluded). § 20.31.035.
  • All property in SP‑11 must be developed/maintained in accordance with the Crescent Heights Specific Plan document incorporated by reference; architectural compatibility requirements and landscape/street‑lighting standards are found in the specific plan text (incorporated). § 20.31.030 and adoption language § 20.31.020.

• Where it applies: Only parcels mapped and shown as SP‑11 on the official zoning map; the specific plan text (August 2002) is expressly incorporated by reference. § 20.31.020.

Practical guidance: If your parcel is in SP‑11, you must follow the SP‑11 Specific Plan (not the baseline R‑ or C‑district standards) and expect site plan/design review scrutiny of exterior alterations and landscape/hardscape changes.

SP‑23 — Heritage Square Central Business District Specific Plan

• Purpose/use: SP‑23 is a mixed‑use specific plan for Heritage Square; it replaces underlying zoning for mapped parcels and establishes its own development and design standards. Site plan and design review is required for SP‑23 projects. § 20.26.010 and § 20.26.030.

• Preservation interface: SP‑23 explicitly references compatibility with the Crescent Heights historic district where adjacent: single‑family homes fronting Rose Avenue within SP‑23 must comply with the Crescent Heights historic front setback requirements (calls out the historic district standard). Check the SP‑23 setback and building‑form rules where your lot abuts SP‑11. § 20.26.030 (applicability) and supporting SP‑23 standards.

• Where it applies: Parcels mapped SP‑23 on the official zoning map. § 20.26.020–.030.

Practical guidance: When a project sits at the SP‑23 / SP‑11 interface, the SP‑23 plan defers to SP‑11 front‑setback/compatibility rules for lots that front Rose Avenue — verify the parcel’s specific designation on the zoning map.

OS — Open Space District

• Purpose: The OS district protects parks, open space, and areas “of outstanding scenic, historical and cultural value” and allows special controls where resource preservation is needed. The district expressly lists protection of areas with historic/cultural value among its purposes. § 20.18.010.

• Typical permitted uses and standards: Parks, recreation, institutional uses consistent with open‑space objectives; development is constrained and subject to specific standards and possible preservation restrictions. See Chapter 20.18 for the range of allowed actions and the modification procedures to preserve scenic/historic values. § 20.18.010 and § 20.18.140.

• Where it applies: Parcels zoned OS on the official zoning map. § 20.18.010.

Practical guidance: If your historic resource sits in an OS parcel, the city has an explicit policy basis for preservation tools such as easements and more stringent design controls. § 20.18.140 authorizes modifications tied to recorded restrictions that preserve historic value.

PI — Public Institutional District

• Purpose/uses: The PI district provides for governmental and public institutional uses (government buildings, schools, museums). Museums are specifically shown as a permitted use category (P) in the PI uses table. § 20.14.010 and § 20.14.020.

• Why it matters for preservation: Adaptive reuse as a museum or institutional use may be an allowed path to preserve historic structures under PI zoning; institutional conversions will still require design review and compliance with SP‑/site plan standards. § 20.14.150 (prerequisites and design review cross‑references).

Practical guidance: If a historic property is or can become public institutional (museum, library), the PI rules and design review process are the control points that define acceptable changes.

Quick reference table — most decision‑relevant preservation rules

Checklist (what an applicant must satisfy for exterior work on a potential historic property)

• Confirm whether the parcel is mapped SP‑11 (Crescent Heights) or another specific plan/overlay that affects historic rules; if SP‑11, supply specific plan compliance materials. § 20.31.020.
• Prepare complete site plan & design review submittal per the requirements of § 20.52.010–.020 (plans, materials, elevations, landscape, lighting).
• If proposing a standards modification tied to preservation (e.g., increased setback, façade easement), prepare the required easement/covenant language and findings under § 20.18.140 (city attorney approval).
• If seeking a ministerial housing allowance (two‑unit project), verify the lot is not historic / not in the State Historic Resources Inventory and satisfy the two‑unit submittal checklist including deed restriction requirements. § 20.10.041.
• Provide photographic documentation and (if requested) the specific plan’s required historical treatment or compatibility report (SP‑11 plan text is incorporated by reference). § 20.31.030.
• Coordinate with the Community Development Department before recording preservation easements or covenant language for standards modifications; the city attorney must approve the form per code. § 20.18.140.

Risks & Ambiguities

Plain‑English summary

If your property is inside the Crescent Heights Historic District (SP‑11) or otherwise identified as historic, you must follow the SP‑11 specific plan and submit detailed plans for site plan and design review; the city can also accept permanent preservation easements in exchange for narrowly tailored deviations to protect historic features. Changes that look minor to you (driveway paving, siding, new windows) are reviewed for compatibility under the SP‑11 rules and § 20.52 design‑review process. § 20.31.010–.035, § 20.52.010–.020, § 20.18.140.

Source References

• Signal Hill Municipal Code, 20.31.010–20.31.035 (SP‑11 Crescent Heights Historic District Specific Plan) — adoption, purpose, standards.
• Signal Hill Municipal Code, 20.52.010–20.52.020 (Site Plan and Design Review requirements).
• Signal Hill Municipal Code, 20.18.140 (Modifications of standards tied to preservation easements/covenants).
• Signal Hill Municipal Code, 20.10.041 (Two‑unit projects — ministerial housing; historic‑parcel exclusion).
• Signal Hill Municipal Code, 20.26.010–.030 (SP‑23 Heritage Square Specific Plan — applicability and design review linkage to historic district adjacency).
• Signal Hill Municipal Code, 20.14.010–.020 (Public Institutional district uses; museums listed).
• State guidance (ADU and historic resources): 2025 ADU handbook excerpt in provided materials; explains that ADUs may be allowed in historic districts subject to objective standards to avoid adverse impacts. Not a local code provision — verify locally.

Retrieved passages

• Signal Hill Zoning Code (chapter by) Medium relevance show source text
• Signal Hill Zoning Code (section will) Medium relevance show source text
• Signal Hill Zoning Code (§ 2) Medium relevance show source text
• CBC § 66411.7 (section applies) Medium relevance show source text
• Signal Hill Zoning Code (Chapter 20.52) Medium relevance show source text
• Signal Hill Zoning Code (§ 66411.7) Medium relevance show source text
• Signal Hill Zoning Code (§ 3) Medium relevance show source text
• Signal Hill Zoning Code (chapter will) Medium relevance show source text
• Signal Hill Zoning Code (§ 65915) Medium relevance show source text
• Signal Hill Zoning Code (chapter shall) Medium relevance show source text
• Signal Hill Zoning Code (Chapter 13.10.) Medium relevance show source text
• Signal Hill Zoning Code (§ 1) Medium relevance show source text
• Signal Hill Zoning Code (Chapter 13.10.) Medium relevance show source text
• Signal Hill Zoning Code (§ 65589.5) Medium relevance show source text
• Signal Hill Zoning Code (section of) Medium relevance show source text
• Signal Hill Zoning Code (§ 6) Medium relevance show source text
• Signal Hill Zoning Code (Chapter 20.58.120) Medium relevance show source text

Cited sections

• Signal Hill Municipal Code, **20.31.010–20.31.035** (SP‑11 Crescent Heights Historic District Specific Plan) — adoption, purpose, standards.
• Signal Hill Municipal Code, **20.52.010–20.52.020** (Site Plan and Design Review requirements).
• Signal Hill Municipal Code, **20.18.140** (Modifications of standards tied to preservation easements/covenants).
• Signal Hill Municipal Code, **20.10.041** (Two‑unit projects — ministerial housing; historic‑parcel exclusion).
• Signal Hill Municipal Code, **20.26.010–.030** (SP‑23 Heritage Square Specific Plan — applicability and design review linkage to historic district adjacency).
• Signal Hill Municipal Code, **20.14.010–.020** (Public Institutional district uses; museums listed).
• State guidance (ADU and historic resources): 2025 ADU handbook excerpt in provided materials; explains that ADUs may be allowed in historic districts subject to objective standards to avoid adverse impacts. Not a local code provision — verify locally.
• SignalHill_ZoningCode.md
• 2025 California ADU handbook.md

• Official Signal Hill code library