The gradual warming predicted by climate change models may foster the spread of invasive species that can adversely impact both source water quality and water utility operations. A recently completed project co-sponsored with the U.S. Environmental Protection Agency, Milfoil Ecology, Control, and Implications for Drinking Water Supplies (2007, order #91207), identified invasive milfoil species that may be of concern to the water supply industry in North America. This research characterized the occurrence, as well as the negative and positive impacts on drinking water utilities, and reviewed known control strategies. A recent workshop co-sponsored by Water Research Foundation, Metropolitan Water District of Southern California, and Southern Nevada Water Authority—“Workshop on Quagga/Zebra Mussel Control Strategies for Water Users in the Western United States” (project #4200)—helped establish the state of current knowledge concerning quagga mussels, an invasive species closely related to the more familiar zebra mussel, that has recently been identified in water bodies throughout the Colorado River system. The workshop focused on biology and reproductive patterns, control methods, and research needs associated with quagga mussels, with particular emphasis on western waterways.