Nalgene – 16oz Narrow Mouth
Weight: 3,75 oz / 106 grams
Volume: 16 oz / 500 ml
A water bottle is not required and other solutions could be a water bladder or simply buying water and use that bottle …even for refills. That would be the lightest solution.
It very different how much water people need for a day hike. But between ½ liter and 2 liters is normal. It is better too have too much in the beginning and then scale down to the necessary after a while.