Public Utilities Code § 16884
ARTICLE 3. Joint Acquisition and Use of Sewage Facilities and Water Works
No agreement under Sections 16880 to 16883, inclusive, shall run for a longer period than 30 years; provided that in case bonds are issued to finance such waterworks, such agreement may be extended until such bonds are matured and redeemed. Any contract made with the federal government or any branch thereof is not subject to this restriction or limitation.