Wild Horse Island, Flathead Lake Northwestern Montana

Wild Horse Island, a state park, rises 700 feet above the pristine waters of Flathead Lake, the largest natural lake west of the Mississippi in the 48 contiguous states. Known for its herd of wild mountain sheep, Wild Horse is accessible only by boat. The island’s hiking trails are extremely popular with day users.A waterless composting toilet provided convenient, odorless, sanitation without polluting groundwater or the lake.

ACS’s prefabricated building features a permananet wood foundation, cement siding for fire resistance and a Trex synthetic wood deck for durability. Solar hot air collectors in the roof heat the insulated basement. Photovoltaic arrays under the roof’s Lexan glazing power the facility’s electrical system. Gutters along the eves channel rainwater into the cistern in the basement.

Rainwater stored in the cistern is pumped to a spray hose in the toilet room to assist in maintenance.