A California resident is subject to California state income tax on all income regardless of where it is earned. Residency refers to where you currently live, while domicile refers to the place you intend to return to after a temporary absence.You must be continuously physically present in California for more than one year (366 days) immediately prior to the residence determination date. If a person is considered a resident of California, they generally have to pay California state income tax on all of their income. According to the California instructions: A California Resident is a person that lived in California permanently for the full year.