California Code, Water Code - WAT § 53225

A demand warrant not paid or presented for reissuance within four years after its date, or a time warrant not paid within four years after its maturity may, upon the demand of the holder, be extended one or more times until repayment or reissuance, for a like period of four years from the date of each extension, upon presentation to the board, such extension being endorsed thereon by the board.