California Code, Water Code - WAT § 74872

If the board determines by resolution that (1) the expenditure of money raised by the sale of bonds for the purpose for which the bonds were voted is impracticable or unwise, or (2) that all of the purposes for which money raised by the sale of bonds have been fulfilled but that there is a surplus of such money remaining, the board may call a special election to obtain the consent of the voters to use the money for some other purpose for which the district may issue bonds.

The procedure shall be the same as when the bond proposition was originally submitted and the election may be consolidated with any other election, in which case one ballot may be used in the discretion of the board.