California Code, Code of Civil Procedure - CCP § 1240.630

(a) Where property is sought to be taken under Section 1240.610, the defendant is entitled to continue the public use to which the property is appropriated if the continuance of such use will not unreasonably interfere with or impair, or require a significant alteration of, the more necessary public use as it is then planned or exists or may reasonably be expected to exist in the future.

(b) If the defendant objects to a taking under this article on the ground that he is entitled under subdivision (a) to continue the public use to which the property is appropriated, upon motion of either party, the court shall determine whether the defendant is entitled under subdivision (a) to continue the use to which the property is appropriated; and, if the court determines that the defendant is so entitled, the parties shall make an agreement determining the terms and conditions upon which the defendant may continue the public use to which the property is appropriated, the terms and conditions upon which the property taken by the plaintiff is acquired, and the manner and extent of the use of the property by each of the parties. Except as otherwise provided by statute, if the parties are unable to agree, the court shall fix such terms and conditions and the manner and extent of the use of the property by each of the parties.