Tree seems to be drying up, but has been watered regularly.
Arizona Sweet Leaves Are Turning Yellow
Certified GKH Gardening Expert
Orange trees planted in the ground will need 1 to 1 1/2 inches of water per week.
If this a newly planted tree you may need to increase this amount.
If this is a potted citrus tree, daily water is generally needed and if temperatures are above 85 degrees you may need to water twice a day.
I am listing some articles to refresh you on the care requirements.