National Water Research and Development Initiative Act of 2008

National Water Research and Development Initiative Act of 2008 - Directs the President to implement a National Water Research and Development Initiative to improve the federal government's role in designing and implementing federal water research, development, demonstration, data collection and dissemination, education, and technology transfer activities to address changes in U.S. water use, supply, and demand.

Directs the President to establish or designate an interagency committee to implement the Initiative, which shall: (1) develop a National Water Research and Assessment Plan; (2) coordinate all water-related federal research, development, demonstration, data collection and dissemination, education, and technology transfer activities; (3) ensure cooperation among federal agencies; and (4) facilitate technology transfer, communication, and opportunities for information exchange with various parties through a National Water Initiative Coordination Office (to be established by the President to provide technical and administrative support to the committee).

Requires the Plan to: (1) establish priorities for federal water research; (2) identify each current program and activity related to the Initiative; (3) identify funding levels; (4) set forth a strategy and timeline to achieve specified desired outcomes, including implementation of a National Water Census; (5) address suggestions and incorporate public input received; and (6) be submitted to Congress within one year of enactment.

Directs the President to: (1) provide guidance to each federal agency participating in the Initiative regarding the preparation of requests for appropriations for activities related to the Plan; and (2) submit, concurrent with the annual budget submission to Congress, a report that describes Initiative activities and results during the previous fiscal year and outlines objectives for the next fiscal year.