To amend the Reclamation Wastewater and Groundwater Study and Facilities Act to authorize the Secretary of the Interior to participate in the design, planning, and construction of a project to reclaim and reuse wastewater within and outside of the service area of the Castaic Lake Water Agency, California.

Amends the Reclamation Wastewater and Groundwater Study and Facilities Act to authorize the Secretary of the Interior, in cooperation with the Castaic Lake Water Agency, California, to participate in the design, planning, and construction of a project to reclaim and reuse wastewater within and outside of the service area of the Agency. Limits the Federal share to 25 percent of the cost of the project. Prohibits the Secretary from providing funds for project operation and maintenance.