(iv) Extension of existing water distribution piping and gravity sewers, eight inches in diameter or smaller, provided that off-site length shall not exceed 1,000 feet, the design and construction of which shall conform to the local government ordinances and regulations, and such extensions shall be subjected to the review and approval of a local government which has been delegated approval authority by the Environmental Protection Division of the Department of Natural Resources, provided that the design of any storm-water management plans, facilities, water distribution lines, and sanitary sewer collection systems shall be performed only by such professional land surveyors who are qualified to do so as provided in Code Section 43-15-13.1;