penalties and costs; districts cooperating with reclamation laws.] All district taxes, tolls and charges of any irrigation district cooperating with the United States under the federal reclamation laws and other federal laws shall be due and payable as follows: first half January 1st of each year; second half July 1st of each year; on February 1 of each year, if the taxes, tolls and charges made the previous year shall not have been paid, one-half shall become delinquent; and on August 1st following, if not paid, the remaining one-half of said taxes, tolls and charges, shall become delinquent; and such taxes, tolls and charges from the respective dates of delinquency, shall bear interest at the rate of one-half of one percent per month until paid; provided, however, that when any such district shall have entered into a contract with the United States requiring the payment of the operation and maintenance costs to the United States in advance, all of such operation and maintenance taxes, tolls and charges, and all taxes, tolls and charges for current and miscellaneous expenses, shall be due and payable on the first day of January of each year, and on February 1st of each year, if the operation and maintenance taxes, tolls and charges, and taxes, tolls and charges for current miscellaneous expenses made the previous year shall not have been paid, all of the same shall become delinquent and shall bear interest at the rate of one-half of one percent per month until paid; and provided further, that the laws as to penalties and costs for delinquent taxes due to the county shall apply to delinquent taxes due to the district.