Cal. Welf. & Inst. Code § 14124.94

(a) When the rights of a Medi-Cal beneficiary to health care benefits from an insurer have been assigned to the department, an insurer shall not impose any requirement on the department that is different from any requirement applicable to an agent or any assignee of the covered beneficiary.
(b) The department, in the administration of the Medi-Cal program, may garnish the wages, salary, or other employment income of, and withhold amounts from state tax refunds from, any person to whom both of the following apply:
1. (1) The person is required by a court or administrative order to provide coverage of the costs of health services to a child who is eligible for medical assistance under the Medi-Cal program.
2. (2) The person has received payment from a third party for the costs of the health services for the child, but he or she has not used the payments to reimburse, as appropriate, either the other parent or the person having custody of the child, or the provider of the health services, to the extent necessary to reimburse the department for expenditures for those costs under the Medi-Cal program. All claims for current or past due child support shall take priority over claims made by the department for the costs of Medi-Cal services.
(c) For purposes of this section, “insurer” includes every health insurer, self-insured plan, group health plan, as defined in Section 607(1) of the Employee Retirement Income Security Act of 1974, service benefit plan, managed care organization, including health care service plans as defined in subdivision (f) of Section 1345 of the Health and Safety Code, licensed pursuant to the Knox-Keene Health Care Service Plan Act of 1975 (Chapter 2.2 (commencing with Section 1340) of Division 2 of the Health and Safety Code), pharmacy benefit manager, or other party that is, by statute, contract, or agreement, legally responsible for payment of a claim for a health care item or service.