Proper selection of appropriate treatment processes for surface water supplies is a function of raw water quality including particles and natural organic matter (NOM). This paper presents an updated foundation for process selection based on routinely measured parameters of particles (turbidity) and organic matter content (UV254, color and TOC). The distinction between mineral and non-mineral turbidity is addressed. Processes considered include direct filtration, conventional sedimentation, dissolved air flotation and contact clarification. The results of this paper are based on a survey of currently operating facilities, pilot studies, theory and North American experience. Recommended guidelines for process selection as a function of raw water TOC, color and turbidity are presented. Figures to aid process selection based on source water quality are provided.