I noticed after I feed my cats with Felidae, they start to drink noticeably more. Could it be related to the food? If so, I would stick to this brand even though there are better brands.
What were they eating before? Anyway, all dry foods are. . .dry :tongue2:, so the more they drink, the better. Some prescription urinary formula dry foods add more salt to make the cat drink more, so maybe Felidae has more salt than what you were feeding them previously. I don't really think the increased water consumption has any renal benefits, as excess salt puts a strain on the kidneys, but it will keep the urinary system flushed out, at least.
Of course, the best way to increase a cat's water intake without adding salt is to feed more canned food. Having a water fountain helps some cats drink more, too.