The Public Utilities Regulatory Authority shall, annually, on or before December thirty-first, or June thirtieth in a municipality which has adopted a uniform fiscal year, furnish to every municipality or department thereof owning, leasing, operating or managing a plant for the supplying or furnishing of any public utility, except water service, blanks for annual reports in such form as the authority may prescribe. Each such municipality or department shall return one of such reports to the authority on or before the following May thirty-first, or the following October thirty-first in a municipality which has adopted a uniform fiscal year, with all questions thereon fully answered. The authority may, for good cause shown, grant an extension of such deadlines of up to sixty days, provided such municipality or department desiring an extension files a request, in writing, setting forth the reasons for such a request. All reports shall be for the year ending December thirty-first, or June thirtieth in a municipality which has adopted a uniform fiscal year and shall be sworn to by the general superintendent of the plant or utility for which the report is required and by such other person or persons as may be designated by such municipality or department. Each such municipality or department shall make such annual reports strictly according to the form provided and, if it finds it impracticable to answer all the items in detail as required, shall state in the report the reasons why such details cannot be given. No such municipality or department shall be excused from giving such details for the reason that it does not keep its accounts in such manner as will enable it to do so. The authority may prescribe the method for keeping the accounts pertaining to such utility, except water service, and all other utilities reporting to the authority. When any such report seems to the authority defective or erroneous, it may notify the municipality making the same and require the amendment of such report within fifteen days from the time of giving such notice; and the authority may examine the officers, agents, employees, books, records, accounts, vouchers, plant and equipment of such municipality or department pertaining to such utility, except water service, and may correct such items in such report as, upon such examination, the authority may find ought to be corrected.