Currently access to the lake is primarily municipal marina of St. Ferdinand. William Lake is located in the watershed of the river Bécancour. It has its source in Lake Bécancour, through William, Lake Joseph and continues on its way to the river, in the city of Bécancour. William lake is fed primarily by the Bécancour River and also by Larochelle River and streams by Gardner, Fortier, Chainey, Masse, Larose and Pinette.