The provisions of this chapter apply to and govern the plumbing system, which includes all potable water supply and distribution pipes from the City main, all plumbing fixtures and traps, all drainage and vent pipes and all building drains and house sewers, including their respective joints and connections, devices, receptacles, and appurtenances within the property lines of the premises and shall include potable water piping, potable water treating or using equipment, fuel gas, piping, water heaters, and vents for the same. For the purpose of this section, the term “plumbing fixture” means an approved type installed receptacle, device, or appliance which is supplied with water or which receives liquid or liquid-borne wastes and discharges such wastes into the drainage system to which it may be directly or indirectly connected. Industrial or commercial tanks, vats, and similar processing equipment are not plumbing fixtures when and as otherwise provided for elsewhere in this chapter.