Nineteenth-century observers from John Wesley Powell to Mark Twain warned that water in the American west is a limited resource. Those observations are especially compelling at the beginning of the 21st century. The pressures on western water are increasing with changing climate, growing population, and increasing environmental regulation. These pressures inevitably generate conflict. Parties to conflicts all too often fight because they rely on unique and parochial data. Evapotranspiration data generated from Landsat are a powerful tool for settling conflicts because Landsat is a single, public, data-source. Eleven western states have developed applications based on evapotranspiration data put out by the METRIC evapotranspiration model using Landsat. In Idaho, these applications include 1) assessment of injury in administering agricultural water-rights, 2) irrigation needs assessment for endangered species protection, 3) analysis of evapotranspiration by land-use/land-cover type for planning, and 4) water-rights negotiations. METRIC results have been used in legal proceedings and are now part of adjudicated decisions.