789.
A tenancy or other estate at will, however created, may be terminated by the landlord’s giving notice in writing to the tenant, in the manner prescribed by Section 1162 of the Code of Civil Procedure, to remove from the premises within a period of not less than 30 days, to be specified in the notice.
Covina Manor v. Hatch(1955) 133 CA2d Supp 790
1] "A tenancy at will is an estate which simply confers a right to the possession of premises leased for such indefinite [133 Cal. App. 2d Supp. 793] period as both parties shall determine such possession shall continue. ... [2] The tenant at will is in possession by right with consent of the landlord either express or implied, and he does not begin to hold unlawfully until the termination of his tenancy. [3] His estate is a leasehold and he holds in subordination to the title of the landlord." (51 C.J.S. p. 762, § 156.) [4] And "A permissive occupation of real estate, where no rent is reserved or paid and no time agreed on to limit the occupation, is a tenancy at will." (51 C.J.S. p. 766, § 159. See also Jones v. Shay (1875), 50 Cal. 508; Hayden v. Collins (1905), 1 Cal. App. 259, 265 [81 P. 1120].) [5] It is equally well settled that "one who enters upon land by permission of the owner under a void parol contract, or under a void lease, or pending unexecuted negotiations for a written lease, is a tenant at will." (Carteri v. Roberts, supra (1903), 140 Cal. 164, 167, and see also Norton v. Overholtzer (1923), 63 Cal. App. 388, 395-396 [218 P. 637].)
Barring a valid rental agreement, it surely sounds like you have a tenancy st will. 30 days notice it is unless there is more to the story.