Dorm configurations used to be pretty standard -- a couple dozen rooms per floor, two people in each room, and one or two bathrooms serving everyone. This bathroom setup gets dirty the quickest.
More modern configurations decrease the number of students per bathroom. Four or eight people may share two or four double rooms with its own bathroom in a suite arrangement.
There's actually a potential upside to the old-school setup: A cleaning staff is usually in there once a week, or even Monday through Friday [sources: Mahmoud, Gerber]. (If the dorm bathroom is never cleaned by anyone, you need to talk to your resident adviser) In a double or a suite, the cleaning might be left to you and your roommates. And if an eight-person bathroom goes without cleaning, over time it will get as filthy as the one down the hall.
Even with a cleaning staff, though, weekends are likely uncovered, and by Sunday night you can find some unpleasant things in the bathroom. There's the usual stuff: musty odor, urine on toilet seats and feces clinging to bowls, mirrors spattered with toothpaste, hair blocking shower drains. In bathrooms without a window or a venting fan, you can also find mildew in as little as 12 to 24 hours after the last cleaning [source: Enviroclean].
And because this is a dorm bathroom, there may also be food in sinks from washing dishes, cigarette butts on window sills, and vomit pretty much anywhere after some Saturday (or Tuesday) night debauchery.
It ain't pretty. But you still need to brush your teeth.
It's an easier problem to deal with in a suite or double. With four or eight people sharing a bathroom, a simple schedule may be all you need. Someone who balks at cleaning the toilet might be more amenable knowing it's only going to be his or her turn a couple times a month. Plus, with fewer people using the bathroom, messes are less anonymous. Shame can be a great motivator. If all else fails, maybe everyone can pool their money to get a housekeeper.
In a configuration where just one or two bathrooms serve an entire floor, you're looking at a more-uphill battle. But it's winnable.