water intake

I read somewhere that a cup a day for a 8lb cat is normal. My cat at 18 lbs 12 years old. (very muscular cat not as a fat as it sounds) has been drinking a lot as previously stated. All tests negative. I'd say he drinks about 2 cups a day so possibly thats not a a bad thing really after all. It also could be Psychological or a nervous habit? People smoke he drinks water?

If all tests are neg and this is a new habit he's picked up, it could be a nervous thing. Any changes around the house? New pet, unusual amount of visitors? Cat's can do some pretty strange things when they're stressed/depressed. If not, then it might not hurt to get a 2nd opinion from another vet. 2 cups seems a bit excessive, even for such a big boy....

And I guess tests mean BW and maybe UA?

Yes blood work and UA