Parents receiving services from the state Child Support Enforcement Agency will have to pay $25 a year for the assistance beginning Oct. 1.

The new fee results from a federal law that will reduce each state's reimbursement based on the number of custodial parents who have had at least $500 collected on their behalf.

The $25 will not apply in any case in which the parent has received Temporary Aid for Needy Families or cash welfare assistance.

Garry Kemp, state child support enforcement administrator, said almost all states have decided to take the fee out of the payments collected for the custodial parent, since that is the person who is receiving the service.

"We had to try to do it the easiest and least expensive way it can be done," he said. "They're going to take the money away from us for each qualifying case."

The state enforcement program spends about $20 million each year to manage about 120,000 support cases. Of that, the federal government reimburses 66 percent.

The Child Support Enforcement Agency is required to get involved in all support cases in which a parent is receiving welfare assistance, Medicaid or child welfare.

In those instances, the $25 fee will not apply.

Custodial parents more likely to be charged are those who are receiving support through a court order or because the custodial parent has applied for assistance in tracking down the absent parent or compelling that parent to pay.

Kemp said monthly support payments can range from about $50 to thousands of dollars a month.

The agency will mail letters explaining the changes to its clients next week, Kemp said.

Congress approved the fee as part of the Deficit Reduction Act of 2005. The federal government estimates about 3.8 million families across the country will pay the $25.