Since they are not tenants, you cannot file an unlawful detainer case, also called an eviction case. But you can file a case for ejectment.
An ejectment case is basically the same as an unlawful detainer but it takes longer.
You can get a free consultation from some of the local attorneys listed here.
If they will not leave voluntarily, you will need to consult an attorney to get them out.
I am sorry but there is no simpler alternative of which I am aware.
A lodger is a person who lives in a room in a house where the owner lives. The owner can enter all areas occupied by the lodger and has overall control of the house. Most lodgers have the same rights as tenants except in the following situation:
In the case of a single lodger in a house where there are no other lodgers, the owner can evict the lodger without using formal eviction proceedings. The owner can give the lodger written notice that the lodger cannot continue to use the room. The amount of notice must the same as the number of days between rent payments (for example, 30 days). When the owner has given the lodger proper notice and the time has expired, the lodger has no further right to remain in the owner’s house and may be removed as a trespasser.
The statute states:
1946.5. (a) The hiring of a room by a lodger on a periodic basis within a dwelling unit occupied by the owner may be terminated by either party giving written notice to the other of his or her intention to terminate the hiring, at least as long before the expiration of the term of the hiring as specified in Section 1946. The notice shall be given in a manner prescribed in Section 1162 of the Code of Civil Procedure or by certified or registered mail, restricted delivery, to the other party, with a return receipt requested.
(b) Upon expiration of the notice period provided in the notice of termination given pursuant to subdivision (a), any right of the lodger to remain in the dwelling unit or any part thereof is terminated by operation of law. The lodger's removal from the premises may thereafter be effected pursuant to the provisions of Section 602.3 of the Penal Code or other applicable provisions of law.
(c) As used in this section, "lodger" means a person contracting with the owner of a dwelling unit for a room or room and board within the dwelling unit personally occupied by the owner, where the owner retains a right of access to all areas of the dwelling unit occupied by the lodger and has overall control of the dwelling unit.
(d) This section applies only to owner-occupied dwellings where a single lodger resides. Nothing in this section shall be construed to determine or affect in any way the rights of persons residing as lodgers in an owner-occupied dwelling where more than one lodger resides.
Please follow up on this with a local attorney.
I hope this information is helpful.