Cal. Water Code § 72072.9

Any tax required to be paid by a service user under the provisions of this article shall be deemed a debt owed by the service user to the district. Any tax collected from a service user which has not been remitted to the board shall be deemed a debt owed to the district by the person required to collect and remit such tax. Nothing in this article shall impose any obligation upon a service supplier to take any legal action to enforce the collection of the utility users tax imposed by this article. Amounts uncollected by a service supplier shall be referred to the board for collection.