California Code, Family Code - FAM § 3751

(a)(1) Support orders issued or modified pursuant to this chapter shall include a provision requiring the child support obligor to keep the agency designated under Title IV-D of the Social Security Act (42 U.S.C. Sec. 651 et seq.) informed of whether the obligor has health insurance coverage at a reasonable cost and, if so, the health insurance policy information.

(2) When an amount is set for current support, the court shall require that health insurance coverage for a supported child shall be maintained by either or both parents if that insurance is available at no cost or at a reasonable cost to the parent. Health insurance coverage shall be rebuttably presumed to be reasonable in cost if the cost to the responsible parent providing medical support does not exceed 5 percent of the parent's gross income. In applying the 5 percent for the cost of health insurance, the cost is the difference between self-only and family coverage. If the obligor is entitled to a low-income adjustment as provided in paragraph (7) of subdivision (b) of Section 4055, medical support shall be deemed not reasonable, unless the court determines that not requiring medical support would be unjust and inappropriate in the particular case. If the court determines that the cost of health insurance coverage is not reasonable, the court shall state its reasons on the record. If the court determines that, although the obligor is entitled to a low-income adjustment, not requiring medical support would be unjust and inappropriate, the court shall state its reasons on the record.