⌂ GRAHAM LARKIN

Landmark Designation and Mills Act Eligibility in Unincorporated Los Angeles County

Overview

Within LA County, there are 88 incorporated cities, each with its own city council, and most with historic preservation ordinances. The areas that are not part of these cities — including such diverse communities as Altadena, East Los Angeles, Florence, Hacienda Heights, Topanga and View Park-Windsor Hills — are under unincorporated County jurisdiction. For the 1 million people living in these places, the Board of Supervisors is effectively their city council, and the area Supervisor their mayor. LA County Departments provide municipal services to these areas.

The LA County Planning department’s historic preservation ordinance outlines the process for designating individual properties, or groups of contributing properties in historic districts, as landmarks. Fifteen properties have been designated as landmarks since the year 2000. In my corporate days I had the pleasure of writing various kinds of documentation for three of the landmarks (Old Glory, the Owen Brown Gravesite and the Bertrand House), nominated in 2024-2025.

County Landmarking

There are many stages in County landmarking, culminating in a landmark designation presented to the County Board of Supervisors by the Director of Regional Planning. The process entails convincing the Board that the property meets the County’s criteria for the designation of an individual landmark (e.g. a historic building of note), or a historic district (e.g. roughly contiguous blocks with a concentration of significant historic buildings that are stylistically unified).

For an individual building to be eligible as a landmark, it must be 50 years of age or older and it must satisfy one or more of the following criteria:

  • It is associated with events that have made a significant contribution to the broad patterns of the history of the nation, State, County, or community in which it is located;
  • It is associated with the lives of persons who are significant in the history of the nation, State, County, or community in which it is located;
  • It embodies the distinctive characteristics of a type, architectural style, period, or method of construction, or represents the work of an architect, designer, engineer, or builder whose work is of significance to the nation, State, County, or community in which it is located; or possesses artistic values of significance to the nation, State, County, or community in which it is located;
  • It has yielded, or may be likely to yield, significant and important information regarding the prehistory or history of the nation, State, County, or community in which it is located;

The ordinance goes on to make exceptions for buildings that have already been formally determined eligible for landmarking on the federal or state level, and it makes some provisions for trees and for exceptional buildings that are less than 50 years old. But the key determinant of landmark eligibility is demonstrating that the exterior elements of a property meet a certain threshold of significance, in keeping with the four criteria listed above. All four criteria are ultimately derived from the National Register for Historic Places, whose standards of proof are subject to stringent guidelines. To know whether your property is eligible for landmarking, be sure to engage the services of a qualified historian.

Mills Act Incentives
Basics

The main incentive for historic designation in unincorporated LA County is eligibility for Mills Act tax benefits. A Mills Act contract will provide the most benefit to owners who have purchased their properties within the last decade at current market-rate prices.

A property does not need to be designated as a County landmark to be eligible for Mills Act funding. But, as noted here, it does need to meet the following criteria:

All of these criteria are ultimately derived from the National Register for Historic Places, whose standards of proof are subject to stringent guidelines. To know whether your property is eligible for landmarking, be sure to engage a qualified historian.

Valuation

The Mills Act valuation caps for unincorporated LA County as follows:

  • For properties individually designated or contributing to the National and California Registers: $1M for a single-family residence; $1.5M for a 2-family residence; or $3M for other land uses.
  • For properties individually designated or contributing to the County Register: $2.1M for a single-family residence; $3.2M for a 2-family residence; or $6.3M for other land uses.

For purposes of a Mills Act contract, a property’s value is determined by the Income Approach to Value, rather than by the standard Market Approach to Value. Do the math to see whether your property qualifies.

Who Benefits from the Mills Act Incentive?

The greatest benefit of historic designation is the potential for a substantial reduction in property taxes through the Mills Act incentive. Participation in the Mills Act program is voluntary and is restricted to owners of designated historic properties. Property owners with comparatively low property taxes, such as those benefitting from Proposition 13 limits on assessed value change over time, will not likely benefit from a Mills Act contract because the assessed value under the Mills Act will likely be higher than the current base-year value of the property. In general, owners who benefit most from a Mills Act contract are those who have acquired their properties in the last 10 years.

Further Incentives

Beyond the incentives listed above, there are more general benefits to having a property formally assessed by a qualified historian. Uncovering the property’s story —including its architects, builders, occupants and renovation timeline, as revealed in a range of written and visual records — can be helpful for:

  • Establishing historic significance for buildings of note, thereby facilitating heritage designation; access to preservation resources including restoration grants and tax incentives; and protection from unwanted alterations;
  • Guiding restoration efforts by ensuring that the materials, construction methods and style are historically appropriate, thus preserving the property’s character and maintaining or increasing its value;
  • Adding market value by demonstrating its association with significant people (e.g. architects, builders, owners, occupants) or events;
  • Legal and planning benefits including facilitation of zoning issues, building permits, or disputes about property modifications, especially in historic districts.

I’m a Pasadena-based architectural historian who has written hundreds of assessments for a wide variety of property owners throughout Los Angeles County.

If you own a property that is more than 50 years old, schedule a consultation to find out whether historic designation is right for you.

If any of these links are broken or incorrect, or if you would like to suggest other resources for preservation in unincorporated LA County, please let me know.

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