When sharing a bathroom with a few folks, you might be asking yourself if more people make an environment more unsanitary, or more liable to make someone sick. The answer seems to be that yes, being around more people does leave you more susceptible to everyday issues like a cold or a stomach bug. So if you're sharing a bathroom, sure you might find yourself exposed to more airborne or contact illness.
But that's a little misleading, because your likelihood of getting sick isn't just a matter of coming in contact with germs. If so, we'd all be sick constantly, with the E coli strains that hang out on our desks or the staph that's present on the kitchen counter. Instead, our health depends on how healthy we are in general. If you have a good immune system -- or even just an OK one -- you're not going to catch every little thing. In fact, it might just be that some people are genetically predisposed to get more colds and viruses [source: Neighmond].
So what does this mean when trying to stay healthy in a dorm bathroom exposed to all sorts of contagious, icky things? Essentially, it comes down to the same things you've been told since you started kindergarten. Good hygiene -- like thoroughly washing your hands in hot water for a full 20 seconds, with attention given to the nails -- does a bang-up job at preventing you from picking up germs you don't want. Getting some sleep (no small order in a dorm) and doing small things like not washing your dishes in the bathroom might go a long way toward keeping your immune system healthy and avoiding cross-contamination [source: Haupt].
So the bottom line is this: You should worry about getting sick from the dorm bathroom about as much as you should worry about getting sick from sitting in the chair of your crowded lecture hall. Although being in an environment that exposes you to lots of germs isn't going to help your health, it probably isn't going to go too far harming it. Your immune system, your hygiene and your genes are really what are keeping you healthy -- or making you sick.