Freshwater/ˈfreʃwɔːtər/ Definition 1 of 3Pro Tip 1/3Ecosystems Variety Freshwater refers to diverse ecosystems beyond lakes, including rivers, streams, and ponds. Freshwater ecosystems are critical for biodiversity. Pro Tip 2/3Species Specificity Many species are 'freshwater' and cannot survive in saltwater. Freshwater turtles need non-salty water habitats. Pro Tip 3/3Not Drinking Quality Not all freshwater is safe for drinking; pollution affects its purity. Despite being freshwater, the river was contaminated.