California: I am the main lease holder on an apartment. I share with someone else who pays a little less than half the lease (per our original written agreement). It has been over 1.5 years, not working out. I asked him to leave on the 1st of this next month and I talked to him about it five weeks ago. As yet, he hasn't made any motion to leave and won't talk with me. I want him out. He leaves lights on, has people here to all hours of the morning and girlfriend stays here two or three nights a week. He doesn't pay the electric bill and pays less than half the lease per our agreement. We were good friends, but he is messy and inconsiderate with the way he shares the place. I want him out. He has been told and makes no effort to move. Today three weeks before he is supposed to move,l am sending him a letter with this notice. Please let me know my rights.

'Main' leaseholder? Only one? If he is not on the lease, you evict him as you would if you were the landlord. You give him written notice to vacate within 30 days starting from the day rent is due, usually the first, so he must be out by August 31. Meanwhile you can start the below. Hopefully you won't need all of it.

Fill out Summons-Unlawful Detainer-Eviction (form SUM-130), the Complaint-Unlawful Detainer (form UD-100) and the Civil Case Cover Sheet (form CM-010). The fee is approximately $160.
Provide a duplicate of the SUM-130 and UD-100 forms to the courthouse in the district or county where you live.
Serve your roommate with the unlawful detainer. In CA, the landlord cannot serve the court papers personally, but can request that another adult not involved in the case serve them. You may also request the court to give you permission to post or mail the papers.

If your tenant does not respond within five days, a judgment will be placed against him and you can legally evict him. However, if the tenant responds with an answer, you must file a Request To Set Case For Trial (form UD-150).

File form UD-150 and mail a copy to the tenant. At this point, both the landlord and tenant have the right to a jury trial. The results of the trial will determine whether you have the legal right to evict your roommate.

However, if he is signed on the lease, you have to work with your landlord to get him out.