California Code, Code of Civil Procedure - CCP § 872.710

(a) At the trial, the court shall determine whether the plaintiff has the right to partition.

(b) Except as provided in Section 872.730, partition as to concurrent interests in the property shall be as of right unless barred by a valid waiver.

(c) Partition as to successive estates in the property shall be allowed if it is in the best interest of all the parties.  The court shall consider whether the possessory interest has become unduly burdensome by reason of taxes or other charges, expense of ordinary or extraordinary repairs, character of the property and change in the character of the property since creation of the estates, circumstances under which the estates were created and change in the circumstances since creation of the estates, and all other factors that would be considered by a court of equity having in mind the intent of the creator of the successive estates and the interests and needs of the successive owners.