Wat. Code, § 9491

Unless otherwise determined by the board or by an order entered in its minutes, a copy of which duly certified shall be transmitted to the county treasurer of each of the counties wherein are situated any of the lands covered by the assessment, the installment for bonds shall be payable in two equal portions, the first of which shall be due and payable to the county treasurers, respectively, on the third Monday in October and is delinquent on the first Monday in December next thereafter at 6 o'clock p.m. and the remaining portion may be paid at any time before the last Monday in April next thereafter at 6 o'clock p.m. at which time the installment is delinquent.