For the purpose of promoting health, safety and the general welfare and to carry into effect the purposes and provisions of sections 341.090 to 341.220, the county commission is hereby empowered to adopt by order rules and regulations for the installations and inspections of all public or private water or plumbing facilities and appurtenances and all installations relating thereto, sewers, sewer systems, water or sewer connections, septic tank or sewage settling tank or device, and all installations related thereto. The regulations shall contain a schedule of fees to be charged for inspections which are required to be made under the provisions of sections 341.090 to 341.220. It shall be the duty of the board of plumbing and sewer inspection to prepare a code of regulations approved by the department of health which shall be submitted to the county commission for adoption. Before the adoption of such code of regulations, the board shall hold at least one public hearing thereon, fifteen days’ notice of the time and place of which shall be published in at least one newspaper having general circulation within the county and notice of such hearing shall also be posted at least fifteen days in advance thereof in four conspicuous places in the county.