Install new or inspect and repair piping systems, including water mains, service lines, sewer lines, air and gas lines, valves, gauges, pumps, and fixtures, including sinks, water heaters, toilets, urinals, and disposals. To assemble, install, and repair piping, fixtures, and equipment used in the distribution and drainage of water and water-carried wastes, air, gas, steam, heating water, and chilled water, under low or high pressure.