From the point of view of ingredients, dry and wet food do not have much in common. Both are usually intended as complete foods. However, cats are originally desert animals, which is reflected in their still quite primitive metabolism despite their long domestication.
Cats take in most of their daily water through their prey. The normally laid prey has a water content of 70%. It is therefore not a natural behaviour of cats to drink a lot of water. A lack of water primarily leads to metabolic disorders, which then become noticeable in the kidneys and urinary tract, among other things. When giving dry food, a water bowl should always be provided as well.