Can cats drink reverse osmosis water?

I myself would not see any issue with providing cats with filtered water. The choice to do that vs. tap water may depend on how much you trust your tap water (well water vs. city water, etc.) and if you have your water tested for heavy metals and other contaminants. My own cats have received both filtered water and tap water and I have not noted a difference either way in my particular case. Regardless of source, water should be changed and refreshed every couple days.