To amend the Reclamation Wastewater and Groundwater Study and Facilities Act to authorize the Secretary of the Interior to participate in the Prado Basin Natural Treatment System Project, to authorize the Secretary to carry out a program to assist agencies in projects to construct regional brine lines in California, and to authorize the Secretary to participate in the Lower Chino Dairy Area desalination demonstration and reclamation project.

Amends the Reclamation Wastewater and Groundwater Study and Facilities Act to authorize the Secretary of the Interior: (1) in cooperation with the Orange County Water District, to participate in the design, planning, and construction of natural treatment systems and wetlands for the flows of the Santa Ana River, California, and its tributaries into the Prado Basin; (2) in cooperation with local governments, to carry out a program to assist agencies in projects to construct regional brine lines to export the salinity imported from the Colorado River to the Pacific Ocean; and (3) in cooperation with the Chino Basin Watermaster, the Inland Empire Utilities Agency, and the Santa Ana Watershed Project Authority, to participate in the design, planning, and construction of the Lower Chino Dairy Area desalination demonstration and reclamation project. Limits the Federal share to 25 percent of total project costs. Prohibits using funds provided by the Secretary for operation and maintenance of the projects. Authorizes appropriations for the Prado Basin and Lower Chino Dairy Area projects.