Texas Family Code - FAM § 154.009. Retroactive Child Support

(a) The court may order a parent to pay retroactive child support if the parent:

(b) In ordering retroactive child support, the court shall apply the child support guidelines provided by this chapter.

(c) Unless the Title IV-D agency is a party to an agreement concerning support or purporting to settle past, present, or future support obligations by prepayment or otherwise, an agreement between the parties does not reduce or terminate retroactive support that the agency may request.

(d) Notwithstanding Subsection (a), the court may order a parent subject to a previous child support order to pay retroactive child support if:

(e) In rendering an order under Subsection (d), the court may order retroactive child support back to the date of the separation of the child's parents.