It appears that the answer is "yes", especially if supplemented by a piece of fruit to replace minerals and nutrients. And even tea and coffee are fine provided that your body is relatively used to dealing with caffeine.
That said, if you're past risk of dehydration, it probably doesn't make that much difference.
From the article:
> Some people worry caffeinated drinks dehydrate us, but this is only true when we drink large doses of caffeine and not enough water.
> Caffeinated drinks do make the body produce more urine, but they also contain water, which will usually more than compensate for the fluid caffeine makes you lose, says Maughan. In fact, he says, tea and coffee are a good way to hydrate because we're likely to drink more of something we enjoy.
> "Coffee contributes to daily fluid requirements, and in regular coffee-drinkers, the kidneys adapt to retain fluid from coffee," she says. "There's no reason moderate amounts of coffee or tea would dehydrate those who are used to having regular caffeine."