Immediately after expiration of the time fixed by the treasurer for the payment of assessments levied under this chapter, he or she shall report to the board in writing the sum collected by him or her and in his or her hands to the credit of the assessment roll; and thereafter and on or before the first days of January and July in each year he or she shall make written reports to said board of the sums collected by him or her upon said roll, stating in detail the amount of principal, interest, and penalty so collected, the amount of principal remaining uncollected, and also, in detail, the principal and interest paid out by him or her under authority of the board, and the balance in his or her hands to the credit of the roll.