Cal. Business and Professions Code § 7044

(a) This chapter does not apply to any of the following: (1) An owner who builds or improves a structure on his or her property, provided that both of the following conditions are met: (A) None of the improvements are intended or offered for sale. (B) The property owner personally performs all of the work or any work not performed by the owner is performed by the owner’s employees with wages as their sole compensation. (2) An owner who builds or improves a structure on his or her property, provided that both of the following conditions are met: (A) The owner directly contracts with licensees who are duly licensed to contract for the work of the respective trades involved in completing the project. (B) For projects involving single-family residential structures, no more than four of these structures are intended or offered for sale in a calendar year. This subparagraph shall not apply if the owner contracts with a general contractor for the construction. (3) A homeowner improving his or her principal place of residence or appurtenances thereto, provided that all of the following conditions exist: (A) The work is performed prior to sale. (B) The homeowner has actually resided in the residence for the 12 months prior to completion of the work. (C) The homeowner has not availed himself or herself of the exemption in this paragraph on more than two structures more than once during any three-year period. (4) A nonprofit corporation providing assistance to an owner-builder, as defined in subdivision (a) of Section 50692 of the Health and Safety Code, who is participating in a mutual self-help housing program, as defined in Section 50078 of the Health and Safety Code. (b) In all actions brought under this chapter, both of the following shall apply: (1) Except as provided in paragraph (2), proof of the sale or offering for sale of a structure by or for the owner-builder within one year after completion of the structure constitutes a rebuttable presumption affecting the burden of proof that the structure was undertaken for purposes of sale. (2) Proof of the sale or offering for sale of five or more structures by the owner-builder within one year after completion constitutes a conclusive presumption that the structures were undertaken for purposes of sale.