How would you tell people politely that you do not want alcohol in your home?

Next year, I am living with one of my current roommates and neither of us drink at all. I have spoken with her about this and she agrees that she does not want alcohol in our apartment. This is for a number of reasons. For now, we are both under 21 and since neither of us drink, if someone was to bring alcohol over, it would just sit in our fridge taking up space. We are also just uncomfortable with the idea of people drinking in our apartment. My mother suggested that we just politely ask people not to bring alcohol over. For most of my friends, I don’t think they will have a problem with that, but I’m worried about the people who will argue with us about not having alcohol in our home. Since this is such a weird and touchy subject with some people, I am turning to fluther.