Santa Clara County has no countywide HPOZ. A handful of cities run their own heritage districts, including Mountain View's Whisman and Old Mountain View, plus Palo Alto's Professorville, where overlay design review applies to exterior changes.
Unlike Los Angeles, Santa Clara County operates no countywide Historic Preservation Overlay Zone over unincorporated land. Within incorporated jurisdictions, three cities maintain HPOZ-style overlays. Mountain View designates two districts under MVMC §36.27, requiring Heritage Preservation Commission review for visible alterations, demolitions, and new construction. Palo Alto's Professorville district under PAMC §16.49 imposes Historic Resources Board approval for exterior changes to contributing structures. Saratoga and Los Gatos use individual landmark designations rather than overlays. Outside these districts, county heritage rules rely on the SCC Heritage Resource Inventory administered by the Department of Planning and Development.
Unpermitted exterior alterations or demolition inside a city HPOZ district trigger stop-work orders, restoration mandates, and per-day administrative fines that can exceed $1,000 plus mandatory CEQA review for repeat infractions.
See how Sunnyvale's hpoz rules rules stack up against other locations.
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