In my refrigerator i have ice tea made from powder mix and water and also there is a jar of plain water. does it matter which i drink every day?

No: Drink which ever. It is important to drink some fluids, and low calorie drinks and water are all great, because you aren't spending caloric intake on heavily sugared and sweetened things that might lead to obesity.

A little: Water has no caloric value, its primary use is in hydration. Depending on the source it may contain trace amounts of minerals like iron or other substances like flouride. The tea contains water as well as the tea mix.Tea has caffeine and if sweetened may have calories, it could provide a slight energy boost not available from water alone. Caffeine may increases urination and heart rate.