The Grand Canyon Water Reclamation Plant in Grand Canyon National Park was one of the first water reclamation plants in the United States, pioneering operating principles that are in use in modern facilities.

It is located on the South Rim in Grand Canyon Village, the center of tourist development in the park.

The scarcity of water and the high demand for fresh water in the developed areas of the park encouraged the development of a system to treat wastewater so that it could be used for non-potable purposes such as flushing toilets, supplying steam locomotive boilers, irrigation and similar uses.

An aeration stage allowed aerobic bacteria to work, followed by a pass through clarifier tanks.

Filters used anthracite coal to give final clarity, followed by chlorination and storage.