Typically, a custodial parent who receives public assistance or gets help from Temporary Assistance for Needy Families must use the state's child support collection unit to get child support from the other parent. Federal law allows the state to seek reimbursement from funds the custodial parent receives from child support payments. As a result, payments, interest and any back support are assigned to the state; the state collects these funds until the assistance the parent has received is paid back in full. If more money is collected than owed, the parent receives the difference.
Any back child support that accumulates is unassigned if the custodial parent has never received any form of state or federal public assistance for herself or her child. The arrears go directly to the custodial parent in this case, even if the custodial parent is using the state collection unit to collect the money. A custodial parent who received public assistance in the past but doesn't anymore is entitled to all arrears that accrue while she's not receiving public assistance.
If the custodial parent had arrears owed to her before she went on public assistance, those past due amounts are temporarily assigned to the state and used to reimburse the state while she is currently receiving benefits. Once the custodial parent stops receiving public assistance, temporarily assigned arrears become conditionally assigned arrears instead. The state only collects money from conditionally assigned arrears if the payment comes from an interception of the noncustodial parent's income tax refund.
If a custodial parent feels she did not receive the support money she was entitled to, she can request a review of her case through the state child support collection unit. The custodial parent has the right to receive statements from her account that show how much support was collected and how much was taken by the state to cover public assistance costs. The local social services department also has information showing how much money the custodial parent and her family received in public assistance.