Owners of properties in historic districts are encouraged to consider their properties’ historic character and develop projects that follow the Secretary of the Interior’s Standards for the Treatment of Historic Properties (often shortened as the Secretary’s Standards). The Secretary’s Standards were developed by the National Park Service to help owners and residents plan sensitive preservation projects.
Depending upon the district and its level of designation (contributor or individually eligible), different restrictions and review processes may apply to newly proposed projects based on locally adopted ordinances and design guidelines. The City of San Mateo’s current Historic Preservation Ordinance requires projects within the Downtown Historic District to adhere to the Secretary’s Standards. The local review process does not currently apply to the contributors of other identified historic districts, and it would not apply to districts that are listed or determined eligible for listing in the California Register or National Register in the future, unless the City’s historic ordinance was amended. However, CEQA review would apply to all projects within any listed or eligible districts (see below).
In the Downtown Historic District, property owners are allowed by right to make minor façade alterations that meet the adopted Downtown Historic District Design Guidelines. Proposals for more substantial alterations to contributors may require the approval of a Site Plan and Architectural Review planning application, as well as review of the project by an independent architectural historian to determine that the proposed scope of work complies with the Secretary’s Standards and the Downtown Historic District Design Guidelines. Infill construction on non-contributing properties may also require analysis by an architectural historian to assess impacts to the surrounding district.
Demolition of a contributor in the Downtown Historic District is not allowed in most cases and would be approved only if the building poses a serious life-safety threat that cannot feasibly be corrected. Such a project would require a Historic Building Demolition Permit to be approved by the City Council, supported by studies documenting the building’s condition, health and safety code deficiencies, and the costs associated with corrective measures.
The California Environmental Quality Act (CEQA) is a state law that establishes a separate review process to assess the impacts of certain types of projects. CEQA covers many areas of the environment, including significant buildings and historic districts (either listed in or eligible for the National Register or California Register). In San Mateo, CEQA review is triggered by projects that require Planning Applications. If one of these projects proposes alterations, demolitions, and new construction in a historic district, the CEQA review process may require an independent architectural historian to analyze the project’s potential impacts to that district. Projects that meet the Secretary’s Standards typically will have a less than significant impact to historic districts and may be exempt from CEQA. More impactful projects may require an environmental document to be prepared, such as an Initial Study or an Environmental Impact Report. Note that CEQA does not necessarily prevent impacts to historic districts, but instead it requires the City and the public to be aware of the impacts to determine whether a project should be approved.
Under CEQA, impacts are usually analyzed to an entire historic district rather than to an individual contributor (unless the contributor itself qualifies as a historic resource). Therefore, substantial alterations or even demolition of a single district contributor that is not individually eligible might not amount to a significant impact if the larger district retains most of its historically or architecturally important qualities.
The National Historic Preservation Act creates its own review process that applies to historic districts listed in or determined eligible for listing in the National Register.
However, this process applies only to projects that receive funding or permits from the federal government, which are not usually initiated by owners of individual properties.