Local zoning · Los Angeles County

Los Angeles County — Historic Preservation

Q: What is a Los Angeles County landmark and who designates it?

A Los Angeles County Landmark is a structure, site, object, tree, landscape, or natural feature that meets the County's criteria (typically 50+ years old and historically/architecturally significant). Designation follows nomination, Director review, hearings before the Landmarks Commission (and possibly the Regional Planning Commission), and final action by the Board of Supervisors; designated County‑owned properties may be done by Board resolution. (§ 22.124.070 , 22.124.090 , 22.124.130 )

Q: Do I need a Certificate of Appropriateness to replace windows or change exterior siding?

If the property is a designated landmark or a contributing property in a historic district , exterior work that affects character‑defining features generally requires a Certificate of Appropriateness , unless it falls into a listed exemption (e.g., routine maintenance). Always confirm with the Director; see § 22.124.140 for triggers and exemptions.

Historic Preservation under the Los Angeles County local zoning and planning code, with the controlling citations.

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Last reviewed: July 3, 2026

Overview

This page summarizes how the Los Angeles County Planning and Zoning Code manages historic preservation in the County's unincorporated areas. The County administers landmark and historic-district designation, review, and enforcement through the Historic Preservation Ordinance (Chapter 22.124) and historic‑district supplemental rules (Chapter 22.82) — see the County code and the Countywide Los Angeles County Zoning & Planning overview for context. Where the rules interact with technical development rules, refer to the County Los Angeles County Zoning and Los Angeles County Development Standards pages; if your project affects vehicle access or parking, see the County parking guidance.

Key takeaways: the County keeps a County Register of Landmarks and Historic Districts; nomination and designation follow a multi-step process with owner notice and hearing requirements; many exterior changes to designated properties require a Certificate of Appropriateness; and historic‑district ordinances can add or supersede development standards for properties inside district boundaries. (See Chapter 22.124 and Chapter 22.82 for the framework.)

How the ordinance works (core standards & responsibilities)

The Historic Preservation Ordinance is codified in Chapter 22.124; its stated purposes include preserving architectural and landscape character, stabilizing property values, and encouraging adaptive reuse in the County's unincorporated areas (§ 22.124.010–22.124.020) .
The County maintains a County Register of Landmarks and Historic Districts; the Landmarks Commission and Director have powers to nominate, study, and administer designations (§ 22.124.050, 22.124.060) .
An owner, organization, the Landmarks Commission, or the Board may nominate a landmark or historic district; nominations trigger owner notice and time-limited review steps (Director report, Landmarks Commission hearing, Regional Planning Commission review, Board action) (§ 22.124.080–22.124.110, 22.124.090–22.124.100) .
When a property is nominated and the nomination becomes effective, development approvals and physical work are restricted until the nomination is resolved unless an application was already deemed complete or the Director determines the work is exempt (§ 22.124.100.C) .
A certificate of appropriateness is required for exterior work affecting a designated landmark or contributing property in a historic district, except for listed exemptions; the Director may exempt maintenance and certain other actions (§ 22.124.140) — note the ordinance explicitly exempts construction of an accessory dwelling unit (ADU) from certificate requirements in certain cases (§ 22.124.140.B.5) . For ADU law interaction, also consult California ADU rules. (/us/california/california-adu-laws)
Historic‑districts are created as supplemental districts and appear on the Zoning Map; property within a historic district remains subject to the basic zone’s permitted uses unless the historic‑district ordinance sets specific development standards that differ (those district standards supersede inconsistent Title 22 rules) (§ 22.82.010–22.82.030, 22.82.040) .

District-by-district breakdown

Note: The County code manages historic resources through the generic supplemental district type Historic District and site-specific landmark designations. The official list of established historic-district names and the Zoning Map entries appear in Table 22.82.040‑A; that table content and the Zoning Map entries were not available in the retrieved materials, so parcel- and district‑specific names and boundaries must be verified with the County (see "Information Gaps" below). Where the Code does set district-level policy it does so by ordinance establishing each district; the summaries below describe the legal framework that applies to every district when the Board adopts one.

Historic District (supplemental district — Chapter 22.82)

Purpose: To implement special development standards and preserve properties of historic importance in the County’s unincorporated areas (§ 22.82.010) .
Typical permitted uses: Any use permitted in the base zone to which the historic district is added; the historic-district ordinance can add conditions or limits (i.e., base-zone uses continue unless the district ordinance says otherwise) (§ 22.82.030.A) .
Key dimensional / project standards: Dimension and design controls for a specific historic district are set in the ordinance creating or amending that district; where those standards conflict with other Title 22 provisions, the district ordinance controls (§ 22.82.030.B) .
Where it applies: Only to properties within district boundaries as shown on the County Zoning Map (Table 22.82.040‑A lists established districts) — verify district names and boundaries with County Planning. (§ 22.82.040)

Los Angeles County Landmark (designation under Chapter 22.124)

Purpose: Recognize and protect individual structures, sites, objects, trees, landscapes, or natural features that meet landmark criteria (§ 22.124.020, 22.124.070) .
Typical permitted uses: Base-zone uses generally remain lawful, but exterior changes, demolition, relocation, or other work may require County review and a Certificate of Appropriateness; recordation of designation is required (§ 22.124.040, 22.124.140) .
Key dimensional / design standards: The Board’s designation resolution or ordinance can adopt guidelines, standards, or restrictions tailored to that landmark; those terms (not a single numeric yard/frontage rule) govern permitted alterations (§ 22.124.130.B) .
Where it applies: To individual properties within the County’s unincorporated areas, and the Board may also designate County‑owned properties as landmarks subject to Board resolution terms (§ 22.124.040, 22.124.130) .

Decision‑relevant table (quick reference)

Topic / trigger	What the Code requires (summary)	Code Reference
When a property is nominated — work freeze	Work on a property subject to an effective nomination (landmark or historic-district nomination) may be prohibited until resolution, except for applications deemed complete earlier or actions exempted by Director (§22.124.100.C).	§ 22.124.100.C
Certificate of Appropriateness required	Required for exterior work on a landmark or property in a historic district and for work affecting character‑defining features; Director may exempt maintenance and other narrow categories (§22.124.140).	§ 22.124.140
ADU construction	The ordinance text notes construction of an accessory dwelling unit can be exempt from Certificate of Appropriateness under §22.124.140.B.5 — verify applicability to your parcel.	§ 22.124.140.B.5
Parking for landmarks	If gross floor area does not increase, a landmark/contributing property shall not be required to provide more parking than existed at designation; added area triggers standard calculation (§22.124.260).	§ 22.124.260
Maintenance obligation	Owners must maintain landmarks/contributing properties to prevent deterioration (§22.124.230).	§ 22.124.230
Enforcement / unauthorized work	Unauthorized demolition/alteration can be declared a public nuisance; County can require full restoration and bar new permits for up to 60 months (§22.124.240.C).	§ 22.124.240
Who decides nominations & appeals	Director, Landmarks Commission, Regional Planning Commission, and Board all play roles in nomination review, hearings, and final designation (§22.124.080–110, §22.124.090–100).	§§ 22.124.080–110, 22.124.090–100

Checklist

Confirm the parcel is inside the County's unincorporated areas and check the County Zoning Map for any historic-district overlay (verify Table 22.82.040‑A / County Planning). (§ 22.82.040)
Determine whether the property is on the County Register of Los Angeles County Landmarks and Historic Districts. (§ 22.124.050)
If the property is nominated or designated, check whether your proposed work needs a Certificate of Appropriateness; if yes, prepare site plans, elevations, materials, and justification per § 22.124.150 application requirements. (§ 22.124.140–22.124.150)
If you plan an ADU, confirm whether the ADU-specific exemption from COA applies and coordinate with the County building rules and state ADU law. (/us/california/california-adu-laws) (§ 22.124.140.B.5)
If proposing demolition, relocation, or major alteration, expect public notice and hearing requirements and potential denial — prepare historic‑resource documentation and economic‑hardship analyses where relevant. (§ 22.124.090–22.124.100, 22.124.180)
Verify parking impacts (waivers or recalculation) via the County parking rules and § 22.124.260.
If in doubt about technical compliance (eg. structural changes), coordinate with County staff and check interaction with the California Building Standards Code. (§ 22.124.060 — Director/Commission powers)

Risks & Ambiguities

Issue	Why it matters	What to verify
Historic‑district names & boundaries	Districts are created by ordinance and mapped on the County Zoning Map; specific district rules are ordinance‑specific and may change base zone rules.	Confirm the district name, ordinance of adoption, and boundaries in Table 22.82.040‑A and on the County Zoning Map (verify with County Planning). (§ 22.82.040)
Which alterations require COA	The Code sets broad rules but the designating ordinance or resolution can add or remove COA triggers.	Always check the specific landmark or historic‑district ordinance/resolution; if unsure, ask the Director whether a COA is required. (§ 22.124.140, 22.124.130)
ADU exemption scope	§ 22.124.140.B.5 mentions ADU construction as an exemption but interplay with state ADU law and site conditions may limit applicability.	Confirm with County Planner and the Building Department; reference California ADU law for state-level rules. (/us/california/california-adu-laws)
Timing when a nomination freezes permits	An effective nomination can stop permit approvals for ongoing projects.	Verify whether your permit application was "deemed complete" before the nomination effective date; if not, expect restrictions. (§ 22.124.100.C)
Enforcement penalties after unauthorized work	The County can require restoration and bar new permits on the site for a defined period.	If work occurred without approval, consult County counsel and expect civil remedies; see § 22.124.240.

Plain‑English Summary

If your property is in the County's unincorporated area and either nominated or designated as a Los Angeles County Landmark or lies inside a Historic District, changes that affect the exterior or character‑defining features will usually require County review and a Certificate of Appropriateness; historic‑district ordinances can add special rules that override normal zoning standards, so always check the County Register, the ordinance that created any district, and talk with County staff before starting work. (§ 22.124.140, 22.82.030)

Information Gaps

The retrieved materials describe Table 22.82.040‑A as the place where established historic districts are listed on the Zoning Map, but the actual district names, ordinance numbers, and dates of adoption in Table 22.82.040‑A were not present in the retrieved files. Not found in retrieved materials. (§ 22.82.040)
Parcel‑level mapping (which addresses are inside each historic district) is not included in the retrieved materials. Verify specific parcel status with County Planning. Not found in retrieved materials.
Any district‑specific design guidelines or numeric dimensional standards (set in the ordinance that establishes a given historic district) are not present in the retrieved materials. Not found in retrieved materials.

Source References

Los Angeles County Planning & Zoning Code — Chapter 22.124 (Historic Preservation Ordinance), including purpose, applicability, nominations, certificates of appropriateness: §§ 22.124.010–22.124.150.
Los Angeles County Planning & Zoning Code — Chapter 22.82 (Historic Districts — supplemental district purpose, development restrictions, Zoning Map listing Table 22.82.040‑A): §§ 22.82.010–22.82.040.
Certificate of Appropriateness application and hearing procedures: § 22.124.150 (application contents and process).
Nomination procedures, development restrictions upon nomination, and timing: §§ 22.124.080–22.124.100.
Maintenance, enforcement, parking waiver and penalties for unauthorized work: §§ 22.124.230, 22.124.240, 22.124.260.
County Register and powers of the Landmarks Commission / Director: § 22.124.050–22.124.060.

Also consult these GoCodebook pages for related operational topics:

Los Angeles County Zoning
Los Angeles County Land Use
Los Angeles County Development Standards
Los Angeles County Parking
Los Angeles County Design Review
Los Angeles County Overlay Districts
California ADU law and the California Building Standards Code for building‑permit and code interactions.

Sources

Retrieved passages

Los Angeles County Zoning Code (Section 22.124.070) High relevance
Los Angeles County Zoning Code (Chapter does) High relevance
Los Angeles County Zoning Code (§ 1) High relevance
Los Angeles County Zoning Code (Chapter 22.124) High relevance
Los Angeles County Zoning Code (Section 22.222.220) High relevance
Los Angeles County Zoning Code (§ 1) High relevance
Los Angeles County Zoning Code (§ 1) High relevance
Los Angeles County Zoning Code (§ 1) High relevance
Los Angeles County Zoning Code (§ 1) High relevance
Los Angeles County Zoning Code (Title 22) High relevance
Los Angeles County Zoning Code (Chapter for) Medium relevance
Los Angeles County Zoning Code (Section 22.124.070) Medium relevance

Cited sections

Official Los Angeles County code library

Frequently asked questions

What is a Los Angeles County landmark and who designates it?

A Los Angeles County Landmark is a structure, site, object, tree, landscape, or natural feature that meets the County's criteria (typically 50+ years old and historically/architecturally significant). Designation follows nomination, Director review, hearings before the Landmarks Commission (and possibly the Regional Planning Commission), and final action by the Board of Supervisors; designated County‑owned properties may be done by Board resolution. (§ 22.124.070, 22.124.090, 22.124.130)

How is a historic district created in unincorporated Los Angeles County?

A historic district is established by ordinance adopted under the processes in Chapter 22.124: nomination, Director report, Landmarks Commission recommendation, Regional Planning review, and Board ordinance that delineates boundaries and contributing properties; once adopted the district is entered on the County Register and shown on the Zoning Map. (§ 22.124.100, 22.82.040)

Do I need a Certificate of Appropriateness to replace windows or change exterior siding?

If the property is a designated landmark or a contributing property in a historic district, exterior work that affects character‑defining features generally requires a Certificate of Appropriateness, unless it falls into a listed exemption (e.g., routine maintenance). Always confirm with the Director; see § 22.124.140 for triggers and exemptions.

Can I build an ADU on a property that is a landmark or in a historic district?

The ordinance text includes an explicit statement that construction of an accessory dwelling unit (ADU) may be exempt from the Certificate of Appropriateness requirement in certain circumstances (§ 22.124.140.B.5). However, ADU construction still must meet state ADU law and applicable County development and building standards — verify with County staff.

Will designation change what I can use my property for?

Designation does not automatically change the base‑zone permitted uses: properties within a historic district "may be used for any purpose permitted in the basic zone" unless the district's ordinance imposes other standards or limitations, which then control. (§ 22.82.030)

What happens if I demolish or materially alter a landmark without approval?

Unauthorized work on a landmark or contributing property can be declared a public nuisance; the County may require restoration to the prior condition and can withhold approval of new permits on the site for up to 60 months (or until restoration) and seek civil remedies. (§ 22.124.240)

Who enforces the Historic Preservation Ordinance and issues COAs?

The Director and the Landmarks Commission administer nominations, COA applications, and enforcement; the Board of Supervisors makes final designation decisions and may adopt resolution terms controlling county‑owned landmarks. (§ 22.124.060, 22.124.130)

Where do I check whether my parcel is inside a County historic district?

Check the County Zoning Map and the County Register (the Code references Table 22.82.040‑A as the list of established historic districts). Because the ordinance that creates a district carries district‑specific rules, verify the district name and ordinance text with County Planning. (§ 22.82.040)

Can the County designate a property without the owner’s consent?

The Code provides notice and a right to object; for historic districts a certification by more than 50% of owners is often required for certain nomination types, and the Director and Boards follow identified consent and hearing procedures — but the County may initiate nominations and proceed through hearings as provided in the ordinance. Verify the exact consent rule that applied to a specific nomination. (§ 22.124.070, 22.124.100)

If my property is in a historic district, will parking rules change?

The Code allows a parking waiver: if gross square footage of a landmark or contributing property does not increase, the owner is not required to provide more parking than existed at the time of designation; increases in gross floor area trigger standard parking calculations. (§ 22.124.260) ---

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