Dry-Redwater Regional Water Authority System Act of 2008 - Directs the Secretary of the Interior to enter into a cooperative agreement to provide federal assistance for the planning, design, and construction of the Dry-Redwater Regional Water Authority System for specified counties in Montana and North Dakota.
Lists agreement requirements. Limits the federal share of planning, design, and construction of the System to 75% of the total cost. Delineates the components of System facilities for which federal funds may be expended and the System's service area. Limits the obligation of funds for construction. Provides that any cost relating to the System's operation, maintenance, or replacement shall not be a federal responsibility and shall be paid by the System.
Directs the Administrator of the Western Area Power Administration to make available to the System a quantity of power required to meet the System's pumping and incidental operation requirements from the water intake facilities and through the water treatment facilities and all first water distribution pumping facilities. Makes the System eligible to receive power only if it operates on a nonprofit basis and is constructed pursuant to the agreement.
Directs the Authority to develop a water conservation plan containing a description of water conservation objectives and measures and a schedule for carrying out such measures. Requires the plan to be designed to ensure that users of water provided by the System will use the best practical technology and management techniques to conserve water.