(a) After the public hearing referred to in § 6504 of this title shall have been closed, the county government shall, by resolution, determine whether or not it is in the public interest to establish the district and, if it deems it to be in the public interest to establish the district, the county government shall, by such resolution, determine the boundaries of the district. Such boundaries may be those set forth in the petition or may be boundaries which will include in the district only the property and property owners that will be benefited by the establishment of the district and the construction of sewage disposal or water facilities therein.
(b) After establishing the boundaries of the district, the county government shall also cause to be prepared by the County Engineer or consulting engineers, an estimate of the cost of proposed immediate construction and also an approximate estimate of the assessment necessary to take care of interest amortization and costs of construction and financing. The construction cost estimates and assessment estimates shall be advertised in the same manner as provided in § 6504 of this title for advertising the public hearing.