California Code, Insurance Code - INS § 10125

(a) On and after January 1, 1974, every insurer issuing group disability insurance which covers hospital, medical, or surgical expenses shall offer coverage for expenses incurred as a result of mental or nervous disorders, under the terms and conditions which may be agreed upon between the group policyholder and the insurer. If the terms and conditions include coverage for inpatient care for nervous or mental disorders, the coverage shall extend to treatment provided at all of the following facilities:

(b) Every insurer shall communicate to prospective group policyholders as to the availability of outpatient coverage for the treatment of mental or nervous disorders. Every insurer shall communicate the availability of that coverage to all group policyholders and to all prospective group policyholders with whom they are negotiating. This coverage may include community residential treatment services, as described in former Section 5458 of the Welfare and Institutions Code, that are alternatives to institutional care.