California Code, Health and Safety Code - HSC § 50692

(a) “Owner-builder” means any person or family who provides all, or a substantial amount, as determined by the department, of the labor necessary to build a housing unit that will be the principal residence of that person or family.

(b) “Owner-building” means the process engaged in by owner-builders in the construction of a principal residence.

(c) “Self-help rehabilitator” means any person or family who provides all, or a substantial amount, as determined by the department, of the labor necessary to rehabilitate, renovate, or improve that person's or family's principal residence.

(d) “Self-help rehabilitation” means the process engaged in by self-help rehabilitators in the rehabilitation, renovation or improvement of their principal residences.