Cats are made up of about 70% water, so they need clean, fresh, cool water daily to maintain their health. If you feed your cats dry food, then water is even more critical as dry food has a very low water content (about only 10%), so they will need an additional supply of water.
It’s critical to always provide your cat plenty of fresh water in various places of your home. Make sure that the bowls are large enough and be sure to clean, wash, and refresh the water bowls at least every other day.
Just because you have larger bowls doesn’t mean you should wash them less. Be sure to wash bowls with soap and water. Bacteria and germs develop quickly when water sits still after a couple of days.
Consider using only glass, stainless steel, or ceramic bowls for water—avoid using plastic for water or food. Plastic can leach out chemicals and can hold bacteria.
The more cats you have the more water bowls you need. We have several in each area of our house and refresh them daily. I like and recommend using large Pyrex glass bowls, they’re very inexpensive, strong, ample, and safe for cats to drink from them.