Make that all-Important Decision Cat Bowl
When choosing a cat bowl this can in fact be a health issue for your cat, ceramic, glass and stainless steel are the better choice of materials. If you consider glass the ingredients in glass are silica, calcium oxide, and sodium carbonate all of which are non-toxic it will not react with acids or other liquids it is also dishwasher safe and can be sterilised and is very stable.
Stainless Steel is generally safe which does not hold germs and does not react with liquids or foods and can be sterilized and is very strong, it is made from iron, nickel, chromium and molybdenum which could leach into foods it the dishware is scratched or in bad shape.
Good Ceramic bowls do not hold germs and if they are manufactured for cats and are food safe then these are fine.
Plastic Bowls are best to avoid they harvest germs and bacteria and cleaning the bowls can still leave them contaminated depending on the manufacturer to how much BPA is a synthetic hormone that is proven to be an endocrine disrupter and can cause chromosomal and reproductive system disorders and cancer. BPA impairs brain and neurological function causes diabetes and obesity and causes cardiovascular system damage also with the bacteria can cause Feline Acne which will show as small black dots and can spread quickly especially if you have a few cats.
If a bowl is close to empty and topped up this can also leave hosts of dangerous bacteria and fungus the can begin to grow, also leave fresh filtered water, not tap water since this has chemicals and mercury in the water and wash bowls not just top them up.