Many of the people on the peafowl forum do put it in the water, but I seriously doubt it's effectiveness and I sure would like to know why people keep doing it even though they keep loosing birds to parasite infestations. Like eggcessive said, it will settle, that is a fact. If one really wanted to use Safeguard (fenbendazole) in the water they could could probably use powdered fenbendazole for fish instead. Either way, you would have to do some math and figure out how much a bird drinks in a day and how much wormer to add. IMNSHO, it's cheaper and more effective to bite the bullet and worm your birds orally.