§48-1-204. Arrearages or past due support defined.
"Arrearages" or "past due support" means the total of any
matured, unpaid installments of child support required to be paid
by an order entered or modified by a court of competent
jurisdiction, or by the order of a magistrate court of this state,
and shall stand, by operation of law, as a decretal judgment
against the obligor owing such support. The amount of unpaid
support shall bear interest from the date it accrued, at a rate of
five percent per annum, and proportionately for a greater or lesser
sum, or for a longer or shorter time. Except as provided in rule
23 of rules of practice and procedure for family law and as
provided in section 1-302, a child support order may not be
retroactively modified so as to cancel or alter accrued
installments of support.