The original decision, 283 U.S. 423 (1931), specified the amount of water to which Arizona was entitled under the Colorado River Compact of 1922.

[1] In summary, as long as at least 7,500,000 acre-feet (9.3 km3) of water is available from the Colorado River, California is allocated 4,400,000 acre⋅ft (5.4 km3); Nevada, 300,000 acre⋅ft (0.37 km3); and Arizona, the remainder.

If less water is available, the Secretary of the Interior must allocate the water according to various formulas (which were the subjects of the court cases) to ensure that each state receives a specified amount, with California receiving an absolute fixed maximum of 4,400,000 acre-feet (5.4 km3) per year (376 U.S.

[2] Some of the adjustments involved rights of the U.S. Government with respect to supplying water to Indian tribes pursuant to Executive Orders signed by the President of the United States as far back as 1907.

The 1962 oral arguments set a modern record for the Supreme Court: 16 hours over four days.