If taxes and assessments shall not be paid at maturity, the collector shall not embrace such taxes in the taxes for which he shall sell the land but shall, on or before the date fixed by law for making settlement with the county treasurer for general taxes, make out and file with the board of directors of the district a list of all real property which lies in the county and which is delinquent for nonpayment of said taxes and retain a copy for use in collecting such delinquent taxes. The board of directors of the district shall enforce the collection of such taxes and the penalties thereon in the manner now provided by law.