Montana Title 40. Family Law § 40-5-304. When child support payments considered delinquent

(1) Nonpayment of child support required by a district court or administrative order or by a similar order of a court of another jurisdiction becomes delinquent under this part 8 working days after the last day of the month in which the payment is due.

(2) Child support payments may be considered delinquent under this part only in reference to a court or administrative order setting child support payments.

(3) Intervening agreements or orders establishing a schedule for payment of delinquent support do not prevent income withholding under this part.