Los Angeles County does not use Historic Preservation Overlay Zones; unincorporated areas instead apply Significant Ecological Areas under Title 22.110.060 for natural resources and Mills Act historic districts for buildings.
The HPOZ designation is a Los Angeles City zoning tool with no county equivalent. Unincorporated LA County protects culturally significant land and structures through two parallel programs. Title 22.110.060 designates Significant Ecological Areas (SEAs) covering Santa Monica Mountains, Antelope Valley, and other natural zones, requiring SEA Conditional Use Permits for development. For built historic resources, the Department of Regional Planning maintains historic districts and individual landmarks reviewed by the LA County Historical Landmarks and Records Commission. Mills Act historic property contracts under Title 22.124 give participating owners property tax reductions. Incorporated cities like Pasadena, Whittier, and Los Angeles operate their own HPOZ or landmark systems separately.
Construction or demolition inside an SEA or designated historic district without the proper SEA CUP or Cultural Heritage Commission clearance can stop work, void permits, and trigger restoration orders and fines under Title 22.110.060.
See how Palmdale's hpoz rules rules stack up against other locations.
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