Often the non-custodial parent makes all payments as required by the court order. For those non-custodial parents who don't make the ordered payments there are a number of ways to force payment. By far the most common and most effective enforcement device is the income withholding order (IWO) - now required in all cases by federal law. If an income withholding order does not work, there are several other methods that can be used to force payment. Because every case is unique, the best method of enforcement is determined on a case-by-case basis.