Answer: If your cat is receiving mainly ‘wet’ diet, then his low water intake almost certainly is not harmful. A low intake usually indicates that the normal body mechanisms for conserving water are working efficiently.
The water required to replace that lost from body in the urine, expired air and the motions is obtained from three sources. Firstly, liquids that are drunk, secondly, moisture in the food and thirdly, ‘metabolic’ water. Metabolic water is water that is created within the body when food is oxidized to produce the energy, and the amount produced is usually fairly constant.
Diets on the other hand can very greatly their water content. Canned foods will captain around 75% water, while at the other extreme dry foods may contain only 8% water. An adult cat of 7 lb (3kg) receiving a ‘wet’ diet will only need to drink about I ¾ fl oz (30 to 50 ml) of water per day to make good its losses; even less if the food has been boiled at home and serve with some of the cooking water. If any additional liquid it could easily be met by a saucerful of milk or water consumed by the cat outdoors e.g. from puddles or guttering. But on a dry diet, up to seven time this quantity of water would need to be drunk. Unfortunately, the often does not adjust its water intake sufficiently to compensate for alternation in the water content of its food. An important factor in the development of blockages in the urinary tract of male cats is their inadequate water intake when receiving a dry diet. Therefore a low water intake by a cat being fed on dry food could harmful and should receive attention.
However, regardless of the type of diet being fed, a bowl of clean water should always be available for the cat. As far as possible discourage drinking from other sources (the skin, toilet bowl, puddles) which could assist in the transmission of disease.
