When valuing enforceably restricted historical property, the county assessor shall not consider sales data on similar property, whether or not enforceably restricted, and shall value that restricted historical property by the capitalization of income method in the following manner:
For purposes of this section, income shall be determined in accordance with rules and regulations issued by the board and with this section and shall be the difference between revenue and expenditures. Revenue shall be the amount of money or money's worth, including any cash rent or its equivalent, that the property can be expected to yield to an owner-operator annually on the average from any use of the property permitted under the terms by which the property is enforceably restricted.
Expenditures shall be any outlay or average annual allocation of money or money's worth that can be fairly charged against the revenue expected to be received during the period used in computing the revenue. Those expenditures to be charged against revenue shall be only those that are ordinary and necessary in the production and maintenance of the revenue for that period. Expenditures shall not include depletion charges, debt retirement, interest on funds invested in the property, property taxes, corporation income taxes, or corporation franchise taxes based on income.
Ca. Rev. and Tax. Code § 439.2