Good question! Not all Keurig models come with a filter holder. If your machine has a little round compartment inside the water reservoir, yes, you have a filter. If not? You’re off the hook—no filter, no problem.
Check your user manual or just peek inside. If you see a tiny plastic basket with a black pouch in it, that’s your filter. Don’t be scared. It’s friendly.
If you don’t have a filter, you can buy an aftermarket filter kit for about ten bucks. But honestly? If your tap water tastes okay, you’re fine without one. No filter shaming here.