Upon the completion or substantial completion of all required appurtenant utility improvements, and the connection of them to the public system, the obligor may notify the Township Committee in writing, by certified mail in care of the Township Clerk, of the completion or substantial completion of the improvements and shall simultaneously send a certified copy thereof to the Township Engineer. Within 10 working days of receipt of the notice, the Township Engineer shall inspect all the improvements as to which the notice has been given and file a detailed report, in writing, with the Township Committee, indicating either approval, partial approval or rejection of the improvements with a statement of the reasons for any rejection. The costs of the improvements as approved or rejected shall be set forth.