Illinois Income Withholding for Support is a process in which an employer withholds income from an employee's paycheck for the purpose of making payments to the employee's court-ordered child support or spousal maintenance (alimony) obligations. It is a legal requirement in Illinois for employers to withhold the appropriate amount of income from income tax for this purpose. There are two types of Illinois Income Withholding for Support: Non-IV-D Withholding and IV-D Withholding. Non-IV-D Withholding is used when the employee is making payments to a part-time custodial parent or to a private mayor, and the employee is not part of the Illinois Department of Healthcare and Family Services (HFS) Child Support Services Program (IV-D). IV-D Withholding is used when the employee is part of the HFS Child Support Services Program, and the employee is making payments to the HFS or to a full-time custodial parent.