We want to politely ask our roommate to leave and are wondering about how to do this nicely while also avoiding any possible legal issues in California

Legally, you may not ask her to move out in the state of California. Her tenancy rights protect her here. - Give her (and the landlord) 30 days notice and move out of the apartment yourselves. - Try asking her to leave, just know you can not force her out. That's it. Those are your choices. Your landlord is not involved, unless either you guys, or roommate, provide 30 days written notice.

Most apartment places I've looked at will let you move to another unit without any of the lease breaking fees or anything like that. If you can move within the complex with your girlfriend without having to take the roommate along for the ride that could be an easy fix.

Yeah, I agree with the above folks saying you find another place just for you and your girlfriend: "oh sorry, but we've decided to get a smaller place, and there won't be room for you!" Tell her YOU are moving, and make sure to take your names off as tenants. She can stay in the current apartment or move, her choice, but it'll cause the least drama in the meantime. As far as the electric bill goes: is there any way you can look up the billing history online, and compare how much you've actually paid Roomie to how much you SHOULD have paid? On the bright side, IF the bill is in her name only, this might be another benefit to your moving out: let her deal with the mess she created. (But double-check to make sure your names are off all utilities, anyway.)

If you're all on the lease, and you're on month to month, you can just say: "We've decided that we'd prefer not to have a roommate. So we're giving you 30-days notice. We'd like to keep the apartment if that works for you." Hopefully it does. If it doesn't, then she's on notice that she's got to find two new room mates, and YOU move out. How the Landlord deals with it from there, is his/her business. Put everything in writing, including notice to the Landlord. Don't list any reasons why you don't want her for a roommate. It's not all that weird for a couple to not want a roommate (She doesn't have to know that you'll be advertising on Craigslist for a new roommate).

The emotional drain of trying (and maybe failing) to force her to move out will last in your memory far, far longer than the temporary physical exertion of planning and executing your own move.

"Roommate, I think it's pretty obvious that this isn't working out. We'd like you to find a new place by [insert reasonable date here]." If you all have equal standing on your agreement/lease with the landlord, she has just as much right to kick you out as you do to kick her out. So you kind of have to start by asking her, politely, to leave. I don't know, but I would guess that any legal action you could take against her would be more difficult than just finding a new place to live. That might be easier if you recruit the landlord to your cause - he/she might be happy to get your roommate out since it sounds like she is grossing up the joint big time (and keeping Christmas trees for six months isn't humorous, it's a crazy fire hazard).

Assuming jbenben is correct, and I assume so, give her the option. Either she moves out and you stay or she finds two new roommates.

I think it's a sleazy tactic, but I've heard of two different people who have had luck in similar situations by talking to the landlord, explaining why roommate is a bad tenant, and asking landlord to sign a new lease (now that yours is up) without roommate on it.

We were in a similar situation. Because all three tenants' names were on the original lease, each of us had a legal right to be there and although we had asked this person to leave, there was no way to force him out. He decided he wouldn't move out and living with him was intolerable, so we moved out instead. We felt it was unsafe to inform him that we were leaving, so we didn't. You don't sound like you're at that point, so feel free to give your roommate a heads up that it won't be possible for you to share accommodations with her any longer. If she won't go, you'll have to move. It's a bad situation, but there's nothing you can do except extricate yourselves as best you can and move on with your lives. One thing to remember is that utility bills can be reported to credit agencies. If she's paying your bill late every month or only paying part of it and all of your names are on the bill, this may affect your credit score and therefore your ability to get another apartment. Deal with that ASAP and get your names removed from the bill if possible.