CA Civ Proc Code Section 1263.610

A public entity and the owner of property to be acquired for public use may make an agreement that the public entity will:

(a)

Relocate for the owner any structure if such relocation is likely to reduce the amount of compensation otherwise payable to the owner by an amount equal to or greater than the cost of such relocation.

(b)

Carry out for the owner any work on property not taken, including work on any structure, if the performance of the work is likely to reduce the amount of compensation otherwise payable to the owner by an amount equal to or greater than the cost of the work.