City taxes shall be due on July first of each year. The treasurer shall not be required to call upon the persons named in the city tax roll, nor to make personal demand for the payment of taxes, but he shall (a) publish, between June fifteenth and July first, notice of the time when said taxes will be due for collection and the penalties and fees for late payment of same, and (b) mail a bill to each person named in said roll, but in cases of multiple ownership of property only one bill need be mailed. Failure on the part of the treasurer to publish said notice or mail such bills shall not invalidate the taxes on said tax roll nor release the person or property assessed from the penalties and fees provided in this chapter in case of late payment or non-payment of the same.