California Code, Revenue and Taxation Code - RTC § 5142

(a) No action shall be commenced or maintained under this article, except under Section 5148, unless a claim for refund has first been filed pursuant to Article 1 (commencing with Section 5096).

No recovery shall be allowed in any refund action upon any ground not specified in the refund claim.

(b) When the person affected or his or her agent and the assessor stipulate that an application involves only nonvaluation issues, they may file a stipulation with the county board of equalization stating that issues in dispute do not involve valuation questions. To the extent possible, the stipulation shall also indicate the parties' agreement as to the assessment amounts that would result under their respective positions on the issue or issues in dispute. The board shall accept or reject the stipulation, with or without conducting a hearing on the stipulation. The filing of, and the acceptance by the board of, a stipulation shall be deemed compliance with the requirement that the person affected file and prosecute an application for reduction under Chapter 1 (commencing with Section 1601) of Part 3 in order to exhaust administrative remedies. However, the filing of, and the acceptance by the board of, a stipulation under this subdivision shall not excuse or waive the requirement of a timely filing of a claim for refund.

(c) Nothing in this subdivision shall be construed to deprive the county board of equalization of jurisdiction over nonvaluation issues in the absence of a contrary stipulation.