Cal. Wat. Code § 12585.3
The local agency may receive credit against its share of the costs of lands, easements, and rights-of-way as determined in subdivisions (b) and (d) of Section 12585.2 for lands required for the project which were acquired not more than five years prior to federal authorization of the project. The amount of this credit shall be determined by the department or the board by applying the percentage representing the state portion of the costs of lands, easements, and rights-of-way as determined in subdivision (a) of Section 12585.2 to the actual costs of the local agency in the case of acquisition by purchase or condemnation, and to the fair market value at the time the title is transferred in the case of acquisition free of charge.
Ca. Water Code § 12585.3