If the cost of a sewer extension as estimated by the City Engineer is less than the amount stated in Ohio R.C. 735.05 for which advertisement for bids is required, the Engineer shall mail a copy of the prints and specifications for the proposed extension as described in the petition to every sewer contractor who is licensed by the City and shall receive bids and enter into a contract with the lowest and best bidder. If the cost is greater than the amount stated in Ohio R.C. 735.05 for which advertisement for bids is required, then the petitioner shall be notified and shall deposit with the City Engineer a sum of money sufficient to pay the cost of advertising for bids. Such advertisement shall be made by the City Engineer in a newspaper of general circulation, for two consecutive weeks and, upon receipt of bids therefor, may enter into a contract with the lowest and best bidder. (1964 Code §303.17)