Irrigation water delivery organizations arose in the late 19th and early 20th centuries to coordinate conveying water across arid farmland in the western United States. They range from small communal ditch organizations, private companies, and nonprofit organizations to large formal quasi-public institutions. Today these organizations play a major role in conveying water to farms, ranches, and other water users in the western United States. The role of these institutions is smaller in parts of the rest of the United States that have more precipitation or where most water is directly pumped from groundwater. According to results from the USDA’s 2019 Survey of Irrigation Organizations (SIO), irrigation water delivery organizations in the western United States managed about 70 percent of water withdrawn for irrigation and almost 60 percent of water withdrawn for all agricultural, commercial, industrial, and municipal uses in an average year.