Cal. Code of Civil Procedure § 1250.410

(a) At least 20 days prior to the date of the trial on issues relating to compensation, the plaintiff shall file with the court and serve on the defendant its final offer of compensation in the proceeding and the defendant shall file and serve on the plaintiff its final demand for compensation in the proceeding. The offer and the demand shall include all compensation required pursuant to this title, including compensation for loss of goodwill, if any, and shall state whether interest and costs are included. These offers and demands shall be the only offers and demands considered by the court in determining the entitlement, if any, to litigation expenses. Service shall be in the manner prescribed by Chapter 5 (commencing with Section 1010) of Title 14 of Part 2. (b) If the court, on motion of the defendant made within 30 days after entry of judgment, finds that the offer of the plaintiff was unreasonable and that the demand of the defendant was reasonable viewed in the light of the evidence admitted and the compensation awarded in the proceeding, the costs allowed pursuant to Section 1268.710 shall include the defendant’s litigation expenses. (c) In determining the amount of litigation expenses allowed under this section, the court shall consider the offer required to be made by the plaintiff pursuant to Section 7267.2 of the Government Code, any deposit made by the plaintiff pursuant to Chapter 6 (commencing with Section 1255.010), and any other written offers and demands filed and served before or during the trial. (d) If timely made, the offers and demands as provided in subdivision (a) shall be considered by the court on the issue of determining an entitlement to litigation expenses. (e) As used in this section, “litigation expenses” means the party’s reasonable attorney’s fees and costs, including reasonable expert witness and appraiser fees.