Legal Question in Family Law in California

The simplest and least expensive way is to open a case with the Dept. of Child Support Services. They can seize brokerage accounts, suspend professional licenses and drivers licenses, put holds on passports, etc., and the ex has no opportunity for a hearing or any other due process unless they initiate it AFTER the seizure, or after receiving notice of the suspension, etc. As an overworked bureaucracy, however, it may not be the quickest way to collect. Filing an OSC re: contempt is usually quicker, because it gets the ex hauled into court in front of a judge to explain why they haven't paid, pay up, or go to jail for contempt, and you can get a hearing in a matter of weeks.

The great news for you is that there is no statute of limitations on child support, meaning that even if the youngest child is over 18, you can still collect, AND interest has been accruing on these arrears at the rate of 10% per annum. Second of all, it's his burden to prove that he made payments, if any at all.

The easiest way to approach this is likely to assign your case to the Department of Child Support Services (it's now controlled by the State, but each county will have its own branch to help you get started). They have enforcement methods that exceed a private practice attorney's abilities. For example, they can suspend his driver's license, take his tax refund, etc.

If you're uncomfortable with assigning your case to them, you can file a motion in Court asking for a repayment arrears schedule. Even though you won't be dealing with red tape from a government agency, this will take time, because you'll have likely multiple hearing dates. If you choose to go this route, you will likely still want the assistance of an attorney to help you come up with a repayment schedule and to assist with the wage assignment.

Good luck!