California Code, Public Utilities Code - PUC § 9512

(a)(1) An annual fee charged by a local publicly owned electric utility for the use of a utility pole by a communications service provider shall not exceed an amount determined by multiplying the percentage of the total usable space that would be occupied by the attachment by the annual costs of ownership of the pole and its supporting anchor. As used in this paragraph and paragraph (2), “usable space” means the space above the minimum grade level that can be used for the attachment of wires, cables, and associated equipment. It shall be presumed, subject to factual rebuttal, that a single attachment occupies one foot of usable space and that an average utility pole contains 13.5 feet of usable space.

(2) An annual fee charged by a local publicly owned electric utility for use of a support structure by a communications service provider shall not exceed the local publicly owned electric utility's annual costs of ownership of the percentage of the volume of the capacity of the structure rendered unusable by the equipment of the communications service provider.

(3) As used in this subdivision, the “annual costs of ownership” is the sum of the annual capital costs and annual operation costs of the pole or support structure, which shall be the average costs of all similar utility poles or structures owned or controlled by the local publicly owned electric utility. The basis for the computation of annual capital costs shall be historical capital costs less depreciation. The accounting upon which the historical capital costs are determined shall include a credit for all reimbursed capital costs. Depreciation shall be based upon the average service life of the utility pole or support structure. “Annual cost of ownership” does not include costs for any property not necessary for use by the communications service provider.