The system is comprised of Core and non-Core Systems. The Core System consists of an intake structure, treatment plant, transmission pipeline, pumping and storage facilities to provide water from Lake Elwell to the residents of the Rocky Boy's Reservation, and on-reservation infrastructure. The Core System is represented by the Chippewa Cree Construction Corporation (CCCC).

The Non-Core System consists of the pipelines, storage and pumping facilities to deliver water from the Core System to the participating systems, including communities, rural water districts, Hutterite colonies, and other rural users in seven counties of north central Montana. The Non-Core System is represented by the North Central Montana Regional Water Authority (NCMRWA).