City taxes and tax collection fees shall be due on the first day of July of each year. City taxes paid or postmarked, if payment is by mail, on or before the following August 31 shall be collected without additional charge. To all taxes paid on September 1 or later the Clerk - Treasurer shall add one-half of 1% for each and every month, or fraction of a month, to the taxes remaining unpaid, together with a collection fee of 4% of the amount of the unpaid taxes. If September 1 is a Saturday, Sunday or a legal holiday, the Clerk-Treasurer shall receive tax payments on the next workday without additional charge. The Council, by resolution, may authorize the Clerk-Treasurer to accept partial payments on taxes and special assessments together with interest and collection charges until the next March 1.