Cal. Wat. Code § 7005
When two or more persons are using any conduit, well, or pumping plant for the conveyance of water or any part thereof for the irrigation of land or for any other lawful purpose, to the construction of which they or their grantors have contributed, and which is not under the control or management of any public agency or authority, any one or more of them may bring an action in the superior court of the county in which the conduit, well, or pumping plant, or some part thereof, is situated, for a declaration of the respective rights of the users of water in the conduit, well, or pumping plant, including a determination of the manner in which the conduit, well, or pumping plant shall be administered with respect to repair, upkeep, improvement, and otherwise.
Ca. Water Code § 7005