 Do I need a reverse osmosis filter if I have a whole home filtration system? Okay, a reverse osmosis system, yes. You can do the tap on the sink, that separate tap for fresh drinking water and run a line to the fridge. So the answer to that question is you can do both. If you get a whole home filtration system, it doesn't hurt to add the reverse osmosis. It's a three-stage system for filtering your water that you're going to drink. I recommend to do both.