Contributing vs. Non-Contributing

Contributing and Non-Contributing are the classifications that the certified Historic Resources Survey assigns to every parcel in an HPOZ. The classification determines which review procedure applies to a given property. The Survey is incorporated by reference into the Preservation Plan; the classifications it makes are binding on the Department of City Planning, the HPOZ Board, and the property owner.

The Department of City Planning’s current public-facing language consolidates the classifications into Contributing (which includes Contributing-Altered) and Non-Contributing for project-review purposes.

A Contributing structure is one identified in the Survey as Contributing — generally because it was built within the district’s Period of Significance and retains elements that identify it as belonging to that period. In some cases, structures built outside the Period of Significance are designated Contributing because they are compatible with the district’s historic context or because they are historic in their own right.

A Contributing-Altered structure dates from the Period of Significance and retains historic character despite alterations or additions, where the alterations are deemed reversible. Some Preservation Plans treat Contributing-Altered as a separate classification; others fold it into Contributing.

A Non-Contributing structure is one identified as not retaining historic character — typically because of irreversible alterations, construction outside the Period of Significance, vacant-lot status, or unpermitted construction.

The classification controls everything downstream. Significant work on a Contributing element triggers a Certificate of Appropriateness. New construction on a vacant lot or replacement of a Non-Contributor triggers a Certificate of Compatibility. Many projects on Contributing properties below the COA threshold proceed as Conforming Work on a Contributing Structure (CWC). Many projects on Non-Contributing properties proceed as Conforming Work on a Non-Contributing Structure (CWNC). The visibility framework, the conforming thresholds, the design guidelines that apply — all of them branch off the Contributing or Non-Contributing determination.

Status is verified by checking the certified Historic Resources Survey for the district. Survey information is also accessible through the City’s Zoning Information and Map Access System (ZIMAS) at zimas.lacity.org, where the HPOZ designation and Contributing status appear with the parcel record. The Office of Historic Resources can confirm classification details that ZIMAS does not display.

A Non-Contributing designation does not exempt a property from review. It changes which review procedure applies. Owners who treat Non-Contributing status as a green light to skip the HPOZ system find out otherwise — through a plan check correction, an enforcement notice, or both.

Source: Each district’s certified Historic Resources Survey, incorporated by reference into the adopted Preservation Plan. Citywide framework established under LAMC §12.20.3 and the procedural framework codified at Division 13B.8 of Chapter 1A LAMC.