Each local government establishes their own criteria and determines how many contracts they will allow in their jurisdiction. For answers to specific questions such as local eligibility criteria, application procedures, and contract terms, contact the city or county official for your jurisdiction. Per the State of California Office of Historic Preservation: Mills Act participants may realize substantial property tax savings of between 40% and 60% each year for newly improved or purchased older properties because valuations of Mills Act properties are determined by the Income Approach to Value rather than by the standard Market Approach to Value. The income approach, divided by a capitalization rate, determines the assessed value of the property. In general, the income of an owner-occupied property is based on comparable rents for similar properties in the area, while the income amount on a commercial property is based on actual rent received. Because rental values vary from area to area, actual property savings vary from county to county. In addition, as County Assessors are required to assess all properties annually, Mills Act properties may realize slight increases in property taxes each year