How much water is a normal amount for a cat to drink?

[Hikari]

Hi. I have an almost 18 year old cat named Maneki Neko, Neko for short. He has had a hyperactive thyroid for about 3 or 4 years which is controlled with medication. At first he was on these soft chewy flavoured pills which he didn't want to eat even though they're suppose to taste good, and even when I mashed them into his food. I now give him the medication in liquid form twice a day. He was also diagnosed with diabetes in October of 2007. I changed his diet to low carb canned food along with giving him the insulin Lantus, and he was in remission within a week. He came out of remission early last December, and I put him on Lantus again, and though it took longer this time, managed to get him back into remission in about a 2 month's time. He tends to throw up once in a while, as we all know cats do, mostly because he was eating too fast or some kind of problem with nausea, and he's fine afterward. I've read a lot from both vets and care givers that cats are not suppose to drink a lot of water, and when they do, it usually indicates a medical problem. That was true with Neko when his diabetes or thyroid acts up, but even when they're both under control, he still drinks quite a bit of water, although not excessively of course like he does when one of his diseases are bothering him. There's still a lot of water left in his dish when I change it in the morning. He doesn't urinate excessively either which he always did when his blood glucose was too high. But the thing I'm concerned about is that he goes through these patterns, he'll drink a lot of water for a period of time, then drink hardly anything at all for another period of time. He threw up after eating on Wednesday, and even though it didn't reoccur, I've noticed he's been drinking more again. I know he was dehydrated after throwing up, but by now he should have slowed down a bit. I have a glucometer at home that I test him with, and his glucose level is within normal range. It doesn't seem like diabetes, even before I tested him to confirm, because his coat is still soft and shiny, and when his BG is in diabetic range, it looks really dull, and feels rough and greasy. I can't tell if it's his thyroid because usually he would be throwing up over and over, and losing weight rapidly. I think he's lost a little weight, but I can't tell for sure because he has fluctuations with his weight as well. The only thing that seems out of place is that he's drinking more than usual, his eating, energy, and coat appear fine. Does anyone else here have a cat that tends to have up and down drinking habits?

[ABC Chinchillas]

I am not sure of normal amounts but an increase in water intake can mean a lot of things. A big one in an older cat is kidney issues. but that does sound similar to when our 20 year old siamese started to have kidney issues a few years ago. we were able to put him on a special diet and had extra time with him before he moved on to a better place. the only way to be sure though is go to a vet

[Hikari]

I'm sorry your kitty got so sick. Renal failure was actually something my vet and I discussed too since it's common in older cats, but his drinking habits aren't so excessive that it would point to anything wrong with the kidneys. He's had these drinking a lot to drinking hardly at all issues going on for a long time, and he's had blood work done. Although his BUN is usually elevated a little, it was because either his thyroid or diabetes was acting up at the time, and the BUN level usually doesn't have much to do with detecting renal failure anyway. The two things that do detect it, (I forget what they're called), were both normal, and this was from last Decemeber. He's do for another check-up with blood work next month, and hopefully everything will still read normal. Even though diabetes and hyperactive thyroid are both nasty diseases, he can live with them. If he gets kidney failure, I know it's terminal, and it would break my heart.