Sufficient water intake is needed to help prevent dehydration, which saps energy, causes fatigue and reduces concentration. The standard 'eight glasses a day' of water, which equates to two litres, has been widely reported as the recommended daily intake of water.
The good news is that tea counts towards that total, particularly in the cooler months. Contrary to popular belief, the caffeine content of a cup of tea is not sufficient to cause a diuretic effect in normal individuals. If you're concerned about caffeine, you needn't be - even 6 cups of tea a day would still mean moderate caffeine intake.
In hot summer months, NSW Health recommends avoiding alcoholic, sugary or hot drinks to limit dehydration.* So when something a little more inspiring than plain water is called for and it's not too hot outside, just put the kettle on.