Monitoring the quality of freshwater supplies is a global concern, especially in thirsty California, where the San Francisco Bay-Delta Estuary and its watershed serve as a major freshwater source. Now scientists at NASA’s Jet Propulsion Laboratory, Pasadena, California, and the U.S. Geological Survey, Menlo Park and Sacramento, California, have successfully demonstrated how a NASA-developed airborne environmental monitoring instrument can be applied to help water managers monitor water quality not only in San Francisco Bay, but potentially in other inland and coastal water bodies around the world.