A parent or person with legal custody of a child can file a petition for Child Support in Domestic Relations. The Virginia Judicial System has a number of forms for each court available on the court's form page.Find the applicable income level under COMBINED GROSS INCOME, then use line 6 (number of children) to determine the basic child support obligation under the. The Department of Social Services shall set child support at the amount resulting from computations using the guidelines set out in this section. Child Support Forms ; 4-7d. Order on Petition for Support of Adult Dependent. Seek expert help from a Fairfax Child Support Modifications Lawyer at Melone Hatley, P.C., for legal guidance on adjusting your child support. If your ex is not paying their court ordered child support and is working under the table, fill this form out and mail to the IRS. This Child Support Calculator allows Virginia parents to reasonably estimate their child support payments. Parents typically want to provide for their children.