Mni Wiconi Project Act Amendments of 2013 - (Sec. 2) Amends the Mni Wiconi Project Act of 1988 to direct the Secretary of the Interior (Secretary) to develop plans for completing, and to enter into agreements with specified agency heads to complete, the Oglala Sioux Rural Water Supply System, the Rosebud Sioux Rural Water System, and the Lower Brule Sioux Rural Water System. Requires such plans to require: (1) the completion of remaining components of the applicable system in accordance with the Final Engineering Report dated May 1993; (2) the improvement, repair, and replacement of existing water systems; and (3) the transfer of those existing water systems to the United States, to be held in trust for the applicable tribe and made part of the applicable rural water system.
Requires the Secretary to enter into agreements with the Administrator of the Environmental Protection Agency (EPA), the Secretary of Agriculture (USDA), the Secretary of Health and Human Services (HHS), and the Secretary of Housing and Urban Development (HUD) to fulfill the trust responsibility of the United States and to complete such water systems in accordance with such Report, including the transfer of existing water systems, as set forth in such plans. Requires: (1) the Administrator to assist the Secretary in meeting the environmental and safe drinking water needs of the Pine Ridge, Rosebud, and Lower Brule Indian Reservations; (2) the HHS Secretary to assist the Secretary in meeting the water supply and public health needs of such Reservations; (3) the HUD Secretary to assist the Secretary by carrying out projects to connect houses that are eligible for funding from HUD on the Oglala, Rosebud, and Lower Brule Sioux Reservations through plumbing, water pipes, appurtenances, and interconnections to the applicable water systems to meet water conservation standards; (4) the Secretary and the Secretary of Agriculture to complete, within 15 years, the livestock distribution systems for the Oglala and Rosebud Sioux water systems; and (5) the Director of the Bureau of Indian Affairs (BIA) to assist the Secretary in completing the Oglala, Rosebud, and Lower Brule Sioux water systems by constructing, repairing, and upgrading plumbing fixtures, skirting, and other necessary features to ensure that houses within the service areas are able to meet the standards for connecting to those systems.
(Sec. 3) Authorizes appropriations under such Act for planning, design, and construction and for operation and maintenance of such water systems.
Requires that, within 15 years of the date on which existing public or tribal water systems on the Pine Ridge, Rosebud, and Lower Brule Indian Reservations have been brought up to the standards for the water systems established in such plans, title to each of the water systems be transferred to the United States, to be held in trust for the benefit of the applicable tribe, upon request of the tribe and the owner of the water system. Directs the Secretary to use authorized appropriations for the improvement, repair, and replacement of any water system that is so transferred or that is proposed, by request of the owner of the water system, to be so transferred and improved.
(Sec. 4) Reduces the maximum amount of the federal share of the cost of the Central Valley Water Recycling Project otherwise available as of the date of enactment of this Act by $15 million.