Drinking a lot is a common sign in older pets and can be the symptom of a number of different diseases. Normally a dog will drink 60-80 ml/kg/day which would be around 600 to 800 ml for a 10 kg dog and an average cat drinks up to 250 ml a day. In older cats chronic kidney disease and hyperthyroidism (overactive thyroid gland) are common conditions that cause increased drinking and weight loss.  Up to