Amends the Reclamation Wastewater and Groundwater Study and Facilities Act to authorize the Secretary of the Interior to participate in a neighborhood demonstration project to: (1) demonstrate the potential for infiltration of stormwater runoff to recharge groundwater by retrofitting sites in the Los Angeles area with features designed to reflect state-of-the-art best management practices for water conservation, pollution reduction and treatment, and habitat restoration; and (2) assess the potential new water supply yield based on increased infiltration and the value of the new water. Limits the federal share to 25% of the project's cost. Terminates the Secretary's authority to carry out this Act 10 years after its enactment.