The rules and regulations or any proposed amendments thereto shall be in writing and a copy thereof shall be posted in a conspicuous place in the office of the district and shall not become effective until 20 days after the posting thereof. The board may require that such rules and regulations or amendments thereof be submitted to it for approval prior to posting. Any person interested may within 10 days after such posting file written objections to such proposed rules or amendments, or any part thereof, with the general manager, in which event the rules or amendments shall not become effective until the general manager has given notice of a hearing and heard objections thereto and announced his decision on the objections.