Boil tap water and let it cool before feeding it to your cat; this is the best and healthiest method. Cats should not drink raw tap water directly, as it contains many bacteria that can easily cause them diarrhea.
Although mineral water and purified water are clean, they are not suitable for cats to drink because these two types of water contain a lot of minerals. If cats drink too much of this water daily, the magnesium ions in the water can easily cause urinary stones. 
There's no need to strictly control the amount of water you give your cat. Just prepare a clean water bowl and always have fresh, boiled water available so your cat can drink freely at any time. That's the best approach.
For cats that don't like to drink water, owners can buy them a running water fountain. Cats generally prefer constantly flowing water, and this method can gradually encourage them to drink. In addition, feeding them wet food can also effectively increase the water intake of cats that don't like to drink water.
