(a) An order of support shall be effective from the date of the filing of the complaint or petition for modification unless the order specifies otherwise. In a child support case, if a change in custody occurs after the date of filing, but before a domestic relations conference is held, the trier of fact shall enter a charging order going forward in favor of the primary custodian that shall be effective from the date of the change in custody. The trier of fact also may enter a retroactive arrears order in favor of the party who was the primary custodian at the time of filing. Such an order may address the period from the date of fining to the date of the change in custody. However, a modification of an existing support order may be retroactive to a date preceding the date of filing if the petitioner was precluded from filing a petition for modification by reason of a significant physical or mental disability, misrepresentation of another party or other compelling reason and if the petitioner, when no longer precluded, promptly filed a petition. Example: Mother has primary custody of the children and files for child support. Two months later, Father becomes the primary custodian. One month after the change in custody, a support conference is held. Father will be the obligee on a charging order that is retroactive to the date he became the primary custodian. However, an order also may be entered with Mother as the obligee for the two-month period from the date of filing to the date of the change in custody.
Every order of support must contain an immediate or conditional order for the attachment of income. See Rule 1910.21.