Plumbers install, repair, and maintain the water supply, waste water treatment, drainage, and gas systems in homes, commercial and industrial buildings. The work includes plumbing tasks to assemble, install and repair pipes, fittings, and fixtures of heating, water, and drainage systems according to specifications and plumbing codes. Plumbers also install sanitary facilities, such as lavatories, toilets, tubs, bathroom fixtures, showers, kitchen fixtures, drinking fountains, and laundry equipment.