My cat Benjamin is a 14 year old neutered male cat who has a very strong odor of amonia upon urinating. He always uses his box. He drinks alot of water and is eating just fine. I have him on a brand name food for older cats. He is a large long haired orange tabby. Other than the strong odor he looks and acts fine and hasn't lost any weight. He has always been a water drinker so I never have questioned that. I'd appreciate anything you may be able to tell me. The amonia smell is a newer thing though and I am concerned.
I recommend a visit to the vet for a blood test and a urine test. This could be a problem with the kidneys or a urinary tract infection. Another possibility is diabetes. Good luck, vetcare