‘Valencia’ orange scions on sour orange rootstock, planted in 1935 at Tempe, Arizona, in calcareous sandy loam, were grown from 1949 through 1968 under 4 irrigation programs: high—15 irrigations a year, 1.72 m water applied; moderate—10 irrigations a year, 1.35 m water applied; low—5 irrigations a year, 0.95 m water applied; high-low—high, March to July, and low, August to February, 9 irrigations a year, 1.18 m water applied. Yields were similar in high, moderate and high-low trees; reduced in low trees. Trunk growth was proportionately reduced as less water was applied. High soil water produced larger tree canopies than moderate, low and high-low, which were similar. Summer shoot growth was stimulated in high trees, limited by fruiting and soil water deficits in moderate and high-low regimes, and promoted by reduced yields in low trees. Low soil water reduced total feeder roots and increased the proportion below 60 cm. Fruit sizes were similar in high and moderate, markedly reduced in high-low and variable in low schedules. Total soluble solids in fruit increased as less water was applied after mid-July. Peel thickness was similar in high and moderate and thinner than in low and high-low. High yields from the high-low regime show there is no advantage in maintaining high soil water during the entire year. Moderate stresses after July induced highest soluble solids in fruit, maintained smaller trees which facilitated picking, and prevented iron chlorosis.