If you’ve ever roomed in a college dormitory, you probably know what it’s like having a roommate. And depending on how things turned out with that roommate, you may either thoroughly enjoy having roomies, or you absolutely despise sharing space with random people.

Maybe you’re one of those folks who loves sharing a place with a couple of friends. But before you enter into any roommate situation, it’s important to lay down some ground rules to help govern the financial and social aspects of having multiple unrelated individuals living under the same roof. So before you ask your best friend from high school to take that empty bedroom in your apartment, consider implementing some of the following basic household laws to help the shared living situation be a smooth and murder-free experience for all.

Finances

• Spell out rent and bill agreements in writing. While many roomie rules can go unwritten, you definitely need confirmation on paper from all parties regarding when their share of rent is due, to whom and how it will be paid, and how utility bills will be divided by each roommate.
• Agree on consequences for missing financial obligations. It’s not just enough to get roommates to agree to pay their bills; they must also know what will happen to them if they don’t. I find that threats of Jell-O all over one’s bed is usually enough to compel on-time rent payments… unless they’re into that sort of thing.

Shared Rooms

• Make shared and unshared rooms painfully obvious. Living rooms and kitchens are generally understood to be common areas shared by all roommates. Your closet, on the other hand, should only be shared by you and yourself. Make sure your other roommates understand this so you don’t come home one day to a wardrobe full of your roomie’s jammies.
• Consider bathroom time limits. This step isn’t needed for most male-only homes, but if you’re in an all-women or coed roommate situation where each person doesn’t have his or her own bathroom, you’ll definitely want to set some reasonable time limits (or even schedules) for bathroom usage.

Shared Supplies

• Agree on what to share and what to keep separate. If your roommate needs to eat 12 pounds of food daily, you may want to clearly distinguish your groceries from his. In fact, keeping consumables separate will just make life easier for you and all of your roommates. Good things to share: plates, small appliances, maybe laundry supplies (as long as you alternate who purchases them), and furniture. Bad things to share: boyfriends and girlfriends (unless you’re into that sort of thing), underwear (unless you’re into that sort of thing), and toothbrushes (unless you’re… eww, nevermind).
• Determine how shared consumables will be replenished. When sharing things like food or laundry supplies, it should be decided who will replace those items when they’re gone. Alternating shopping responsibilities is a good method for this, so long as each roommate contributes roughly the same amount of money to each shopping trip. If you’re bringing home filet mignon and your two roomies only provide ramen noodles, you might want to reconsider the food-sharing situation.

Guests

• Schedule guests in advance. Make it clear to roommates that everyone (including yourself) must schedule overnight houseguests making use of spare bedrooms or couches in advance. This way, you avoid situations where Roommate A invites Mom and Dad to visit while Roommate B is entertaining two Swedish exchange students and oh here comes Roommate C with the entire lineup of the 1997 San Francisco 49ers.
• Define “guests.” Simply read the following statement to your roommates on Day One: “If they stay for up to 48 hours, they are guests. If they stay later, they are rent payers.”

Sexual Tension

• Ties on the door? Agree on how to handle those special overnight friends. In the best of roomie situations, you won’t need to do anything differently because you already knock before entering your roommate’s bedroom. Make it clear that do-not-disturb signs on the front door of the whole apartment are not valid because you live there too.
• For those lonely and desperate nights… If you’re in the situation of living with members of the sex to which you are attracted, there could be periods of time where neither of you is meeting his or her sexual quota (i.e. “not getting any”). You may be tempted to turn to each other to temporarily satisfy your hormonal urges like they do on TV sometimes. Just remember that you have to keep living with that person afterwards, so consider scheduling future rendezvous with that roommate for your mutual convenience what that will do for your rooming situation.

Other Rules

• Don’t just assume house rules are understood by example. If you want to live by an “if it’s yellow, let it mellow; if it’s brown, flush it down” rule, bring it up verbally with your roommates first before demonstrating it.
• Make communication easy. Avoid those “oh, I told you about that three days ago” incidents by having a central communication hub in your shared home. A large whiteboard by the front entrance works great.
• Spell out chores and responsibilities. You can also use that communications whiteboard to assign household chores. It’s best to rotate them each week so you don’t get a roommate who want to shove your head in the toilet they clean every single week.

What else would you consider to be an important ground rule roommates should establish?