Nonresidents and PartYear Residents File a California tax return if you have any income from California sources and your gross income (which. A declaration is a simple statement that you intend in good faith to return to the United States to resume your domicile.Domiciled in California, but outside California for a temporary or transitory purpose. There are more factors for determining residency. Providing proof of domicile in the United States is critical for most people when submitting Form I864, Affidavit of Support. A good tax attorney can help convince California that you don't actually live here and therefore should not pay state taxes. Guide to Completing UCLA Statement of Legal Residency.