Warm Weather

• Healthy cats naturally drink more water during hot weather to replace fluids lost to evaporation and perspiration. Your cat needs access to more fresh water during hot spells, so you may see less water in the bowl at the end of the day. Keep your cat's bowl filled with clean water during hot weather. Monitor your pet's drinking when cool weather returns.
  
  

Dry Food

• If you recently switched your cat's diet from from canned or fresh-cooked food to dry food, it will likely drink noticeably more water. Canned cat food supplies as much as half of a cat's daily fluid intake. Switching to dry food will make the cat head to the water bowl to fulfill the rest of its water needs. Solve the problem either by supplying the cat with canned food or by providing your pet with multiple sources of fresh, clean water.
  
  

Hyperthyroidism

• Middle-aged and older cats are prone to hyperthyroidism, an overproduction of thyroid hormones. Signs of hyperthyroidism include excessive drinking, excessive urination, weight loss, excitability and a palpably swollen thyroid gland at the base of the cat's neck. Your veterinarian will perform a blood test to check levels of thyroid hormones in your cat's bloodstream. Treat hyperthyroidism with medication, surgery or radioactive iodine injection according to your veterinarian's recommendations.
  
  

Diabetes Mellitus

• Cats, like humans, are susceptible to diabetes mellitus, a serious endocrine disorder that affects insulin production or utilization. Approximately one in 400 cats will develop diabetes. Watch for rapid weight loss despite increased appetite, vomiting, hair loss, bad breath and a dull, dandruff-laden coat in addition to the excessive thirst and frequent urination that are hallmarks of diabetes. Your veterinarian will give you a definitive diagnosis after performing a blood glucose test. Feeding your cat a specialized diet may control mild cases. Otherwise, your veterinarian will recommend insulin injections.
  
  

Chronic Kidney Disease

• Cats with chronic kidney disease exhibit excessive thirst, lackluster coats, rapid weight loss and frequent urination. Causes of kidney disease include hereditary defects, infection, consumption of antifreeze or other toxins, or high blood pressure. Take the animal to a veterinarian to distinguish this potentially serious condition from diabetes or hyperthyroidism. Your veterinarian will perform a series of blood tests and urinalysis to diagnose kidney disease. Remedy any underlying cause of kidney disease to prevent further damage to the cat's kidneys and follow the course of treatment your veterinarian recommends.