“In S. (D.B.). v. G. (S.R.), 2006 SCC 37, at para. 134, the court stated that “generally” a court should make “the award retroactive to the date when effective notice was given to the payor parent. But where the payor parent has engaged in blameworthy conduct, the date when circumstances changed materially will be the presumptive start date of the award.” The court described the “date of effective notice” as the “default option”. Once effective notice has been given, “the peer parent can no longer assume that the status quo is fair, and his/her interest in certainty becomes less compelling”, at para. 121. The court added that awarding child support from the date of effective notice maintains a fair balance between certainty and flexibility, at para. 122. At paragraph 125, the court summarized its conclusions: “payor parents will have their interest in certainty protected only up to the point when that interest becomes unreasonable. In the majority of circumstances, that interest will be reasonable up to the point when the recipient parent broaches the subject, up to three years in the past.”
The court, at para. 99, did leave open the possibility that “retroactive support could be ordered where a payor parent engages in no blameworthy conduct.” However, the court described that outcome as “conceivable”.
In paragraph 133, the court summed up its discussion of retroactive child support awards by saying:
In determining whether to make a retroactive award, a court will need to look at all the relevant circumstances of the case in front of it. The payor parent’s interest in certainty must be balanced with the need for fairness and for flexibility. In doing so, a court should consider whether the recipient parent has supplied a reasonable excuse for his/her delay, the conduct of the payor parent, the circumstances of the child, and the hardship the retroactive award might entail.”