A common reference is roughly fifty to sixty milliliters of total water per kilogram of body weight daily, but that total includes the moisture in food.
Cats on complete wet food already get much of their water from meals and may drink little from a bowl, while dry-food cats must actively drink more.
Offer water in several locations, try fountains or slightly warmed water, add broth to wet food, and watch urine clump size as an indirect gauge.
A sudden, sustained rise or drop in drinking can signal illness; if it lasts several days, see a vet rather than assuming a habit change.
