California Code, Family Code - FAM § 915

(a) For the purpose of this part, a child or spousal support obligation of a married person that does not arise out of the marriage shall be treated as a debt incurred before marriage, regardless of whether a court order for support is made or modified before or during marriage and regardless of whether any installment payment on the obligation accrues before or during marriage.

(b) If property in the community estate is applied to the satisfaction of a child or spousal support obligation of a married person that does not arise out of the marriage, at a time when nonexempt separate income of the person is available but is not applied to the satisfaction of the obligation, the community estate is entitled to reimbursement from the person in the amount of the separate income, not exceeding the property in the community estate so applied.

(c) Nothing in this section limits the matters a court may take into consideration in determining or modifying the amount of a support order, including, but not limited to, the earnings of the spouses of the parties.