Sustainable water management is one of the most challenging issues of our time, especially in the arid western U.S. Maximizing the benefits of water supplies requires careful measurement of availability and use. However, one important information gap is compounding this challenge: the lack of consistent consumptive water use data for irrigated agriculture and other vegetated landscapes. To date, access to this data has been limited and expensive, keeping it out of the hands of most water users and decision-makers who could really benefit from its use. OpenET aims to change this and support sustainable water management and innovation in water conservation with an online platform for mapping evapotranspiration (ET) at the scale of individual fields. OpenET uses best available science and publicly available data to increase access to satellite-based ET and consumptive water use information for farmers and water managers. This talk will provide an introduction to the OpenET platform and the approach taken to its development, and demonstrate a few of its applications.