The term "water reclamation" can be defined in different ways. In the early and mid-1900s, water reclamation referred primarily to supplying potable water to arid areas where water was not readily available, through the development of water projects such as dams and canals. Water reclamation can also mean collecting used water (i.e., wastewater) and treating it for reuse for irrigation and other purposes.

The federal agency primarily responsible for water reclamation projects that provided a source of water to arid lands is the Bureau of Reclamation,in the Department of the Interior. Formed in 1902 as the Reclamation Service and later renamed the Bureau of Reclamation in 1923, the agency's mission was "the construction and maintenance of irrigation works for the storage, diversion, and development of water for the reclamation of arid and semi-arid lands." This federal agency built dams, reservoirs, and other water development projects...