Do child support arrears expire in the United States?
Generally no. Child support arrears (past-due amounts) are treated as a debt judgment in most states and do not expire the way other debts do. They can be collected long after the child turns 18. Some states have their own statutes of limitations on arrears enforcement, but federal law requires states to keep IV-D cases open until arrears are paid.
Can I modify retroactive child support?
Courts will not retroactively reduce child support below what was owed under a valid order — only future payments can be modified. However, you can seek credit for informal payments made (cash, direct to child) if you can prove them.
What happens if the payor doesn't pay child support?
Federal and state enforcement tools include: wage garnishment, tax refund interception, bank account levy, license suspension (driver's, professional, recreational), passport denial, and contempt of court (jail). The Office of Child Support Services (OCSS) enforces these automatically in most states.