Cal. FAM § 5610

For the purposes of this chapter, “private child support collector” means any individual, corporation, attorney, nonprofit organization, or other nongovernmental entity who is engaged by an obligee to collect child support ordered by a court or other tribunal for a fee or other consideration. The term does not include any attorney who addresses issues of ongoing child support or child support arrearages in the course of an action to establish parentage or a child support obligation, a proceeding under Division 10 (commencing with Section 6200), a proceeding for dissolution of marriage, legal separation, or nullity of marriage, or in postjudgment or modification proceedings related to any of those actions. A “private child support collector” includes any private, nongovernmental attorney whose business is substantially comprised of the collection or enforcement of child support. As used in this section, substantially means that at least 50 percent of the attorney’s business, either in terms of remuneration or time spent, is comprised of the activity of seeking to collect or enforce child support obligations for other individuals.