Gov. Code, § 64626

(a) In any judicial action or proceeding to validate, attack, review, set aside, void, or annul any resolution providing for the establishment, increase, or imposition of a commercial linkage fee pursuant to this article in which there is an issue whether the fee is a special tax within the meaning of Section 50076, the executive board and the authority shall have the burden of producing evidence to establish that the commercial linkage fee does not exceed the reasonable cost of providing the housing necessitated by the commercial development project for which the commercial linkage fee is imposed, as determined in the regional nexus study pursuant to subdivision (b) of Section 64621.

(b) A party may only initiate an action or proceeding pursuant to subdivision (a) if both of the following requirements are met:

(1) The commercial linkage fee was directly imposed on the party as a condition of project approval, as provided in Section 64624.

(2) At least 30 days before initiating the action or proceeding, the party requests that the executive board and the authority provide a copy of the documents, including, but not limited to, the regional nexus study prepared pursuant to subdivision (b) of Section 64621, that establish that the commercial linkage fee does not exceed the reasonable cost of providing the housing necessitated by the commercial development project for which the commercial linkage fee is imposed. In accordance with subdivision (a) of Section 7922.530, the executive board and the authority may charge a fee for copying the documents requested pursuant to this paragraph.

(c) For purposes of this section, costs shall be determined in accordance with fundamental fairness and consistency of method as to the allocation of costs, expenses, revenues, and other items included in the calculation.