The District contracts with the Bureau of Reclamation for its water supply, which is managed and used conjunctively with groundwater for the long-term irrigation needs of District growers. DEID holds the largest Class 1 contract in the Friant Division of the Central Valley Project totaling 108,000 acre-feet, nearly 14 percent of the total firm yield. DEID also contracts for a smaller amount of Class 2, 74,500 acre-feet. Because of the nature of Friant water supplies, annual District water supplies have ranged from a low of 34,000 to as much as 171,000. The most recent ten-year District average annual water supply is 120,300 acre-feet.
The District also contracts on an opportunity basis for water that can be delivered to lands not otherwise eligible to receive Friant water. Approximately 9% of the lands in the district are deemed ineligible to receive Friant water due to Federal Reclamation Law restrictions. Non-RRA water is typically obtained through mutually beneficial exchanges with other Friant districts with local non-Friant water supplies.