Cal. Health & Safety Code § 1357.05

Except in the case of a late enrollee, or for satisfaction of a preexisting condition clause in the case of initial coverage of an eligible employee, a plan may not exclude any eligible employee or dependent who would otherwise be entitled to health care services on the basis of an actual or expected health condition of that employee or dependent. No plan contract may limit or exclude coverage for a specific eligible employee or dependent by type of illness, treatment, medical condition, or accident, except for preexisting conditions as permitted by Section 1357.06.