Domestic cats originated thousands of years ago from wild cats who lived in dry, arid regions. Therefore, they do not drink as much as other mammals such as dogs. As a result, cats can be more prone to certain urinary or kidney diseases. To help maintain your cat's proper health, consider having multiple water sources available, as well as to offer canned food to help maintain proper hydration. Some cats even like having water mixed into their canned food, since it creates additional "gravy".
Each cat varies in their preferred drinking vessels and types of water. Some cats prefer their water straight from the tap, even literally with some cats liking to drink a trickle directly from a sink or tub faucet. Other cats like to drink from a human drinking glass on an elevated surface, such as a bedside table. Certain cats prefer wide, flattened bowls, so that their whiskers do not brush the sides of the dish as they drink. There are also cats who enjoy drinking from pet fountains, specially designed to provide moving, filtered water. Some cats may show preference for filtered, purified, or distilled water, over regular tap water. The occasional cat may even enjoy ice added to their water dish. Experiment with different choices for you cats in order to determine their preference.
As a result of certain diseases, some cats drink way more water than they should. You can read more about those diseases here.