This is a little bit worrying. Cats really don’t have much of a thirst drive, and “normal” urine output should only be a couple pee-clumps a day for one cat. Is your kitty chubby? One of the first signs of diabetes in a cat is excessive drinking and urinating. If he’s not chubby, sure he could just be an unusual guy, but getting him checked out might be a good idea if he hasn’t been recently.
(vet tech who trains clients on diabetes management)
As to the wet/dry food debate, the feline specialists I work with all recommend canned food for cats. Now, I don’t get all hard-lined on people about it, but cats really do better healthwise with canned food. There are always exceptions, and some cats do fine on kibble, but especially for cats with weight problems, nearly all those issues can be resolved by switching to canned. Even “piggy” cats who love to eat a lot, can lose weight more easily by giving them all the canned food they want rather than restricting kibble or using wight-control kibble. Again, there are always exceptions to the rule, so I pare it down to owners doing some research and making educated decisions on what’s best for their cat’s health and the household budget and schedule.
As to the “better for teeth” argument, it’s just not true. There are two brands of prescription-only kibble out there that are “dental diets.” These are much larger kibble than what is normally fed to cats, and are manufactured in a different way. The small, readily available kibble that people can buy at stores does not clean the teeth at all. One or two crunches, and it’s swallowed. This kind of kibble crumbles. Some cats don’t even do that, and swallow it whole. Regular kibble is put together in a way like a meatball. The ingredients are sort of pressed together, and crumble apart without much effort. The prescription kibble is larger, and requires some chewing for the cat to get it small enough to swallow. Also, the prescription kibble is sort of extruded, think more like taffy, and cut apart. This results in the ingredients being lined up and not crumbling so easily, so the cat really has to slice the pieces apart with his/her teeth, resulting in the kibble actually scraping up and down the molars to the gumline. That’s what actually keeps the teeth cleaner. This size and formula of kibble is not appropriate for all cats, and that’s why it’s prescription only.
The bottom line as far as keeping cat’s teeth clean, is to use enzymatic toothpaste and to brush their teeth, or get dental cleanings done regularly with their veterinarian. There are some (enzymatic) additives that can be purchased, either added to food or water, that are not harmful but are debatable as to how effective they really are.