The short answer: keep the bowl
Yes, a bearded dragon should have a water bowl in its enclosure even if it eats greens enthusiastically. The reasoning is not that greens fail to hydrate — a dragon eating a good volume of collards, dandelion, and squash takes in real moisture with every meal — but that drinking behavior varies too much between individuals to take the option away. Some dragons drink rarely and briefly, often at dawn or when the enclosure is quiet; you may simply never witness it.
How dragons actually take in water
Bearded dragons come from arid country and are economical with water, but they are not cacti. In the wild they lap dew and rain from surfaces, and in captivity many drink most readily from moving or glistening water: droplets sprayed on the glass or on their greens, a gentle drip onto the snout, or the bath during a soak. A dragon that ignores a still bowl may drink eagerly from dripped water — that is a preference, not proof it needs no water source.
Greens contribute the baseline. Bathing contributes too: a lukewarm soak up to the elbows once or twice a week lets a dragon drink and helps loosen shedding skin. Neither removes the reason for the bowl, which is availability at the moment the animal wants it.
Choosing and placing the bowl
Pick a bowl that is low, heavy, and stable — ceramic or stone-style dishes resist tipping when a dragon climbs in. It should be wide enough for the dragon to sit in if it chooses, and shallow enough that the water is never deep on the animal; a healthy adult manages a low bowl easily, and shallow water is the safe side for any dragon. Place it on the cool side of the enclosure so it does not warm and turn the vivarium humid, which still water in the hot zone will do.
Refresh the water daily and wash the bowl when you do. Dragons have a well-known habit of fouling their own water, and a bowl that looks questionable will not be drunk from — quite reasonably.
The dragon that never drinks
If your dragon eats greens well, produces regular droppings with a white urate portion that is not chalky or hard, and never touches the bowl, it is probably hydrating adequately from food and baths. Signs worth a vet conversation are different: sunken eyes, wrinkled skin that stays tented when gently pinched, lethargy, and hard, orange-tinged urates suggest the dragon is not getting enough water despite everything.
Misting, the other water routine
Many keepers pair the bowl with a light morning misting of the enclosure's cool end and the dragon's greens, which imitates the dew-drinking the species evolved with. A dragon that ignores the bowl will often lap droplets from a leaf or from its own snout after misting, and watching for that response tells you more about its hydration habits than the untouched bowl does. Keep misting light and targeted — the aim is drinkable droplets, not a humid enclosure — and let the vivarium dry out fully between mistings so the air stays as arid as the species needs.
The daily water change is the most forgettable job in the enclosure, especially in a shared household. Listing it as a named recurring task in KinsLe Care Teams — marked complete with a timestamp when the bowl is washed and refilled — keeps a small job from becoming the gap in an otherwise careful routine.