Two parents separate when their son is six. They agree on $400 a month, on a handshake or in a brief agreement. Over the next five years, the father’s income climbs steadily with overtime and a promotion. Nobody revisits the number, and the mother never sees a tax return. When the boy turns eleven and needs braces and hockey fees, she finally asks what his father is actually earning. The answer leads to a question that many Brampton parents eventually face: can she go back and claim the difference?
The answer is often yes, but it depends on how far back she can go. Child support belongs to the child, and a parent’s obligation to pay in line with their income exists even where no order has pinned it down. At the same time, the law recognizes that a sudden demand for years of past payments can be unfair if it comes completely out of the blue. Retroactive cases are about balancing those concerns.
This is general information about Ontario and federal law, not legal advice. The hypothetical families in this article are invented for illustration, and small facts can change the result.
What “retroactive” means here
A retroactive order is one that makes support payable for a period before the order was made, or before an application was filed. It is not a claim for overdue payments already fixed by an order. If an order already said $600 a month and the payor did not pay it, that is arrears, which the Family Responsibility Office may enforce without any further ruling on the amount.
Retroactive claims tend to arise in three ways:
- No order or agreement ever existed. A parent paid nothing, or paid an informal amount, for a period of time.
- An order or agreement exists but the income has risen. The amount was based on an income that is out of date.
- A payor’s income has fallen. The payor asks to reduce past amounts and perhaps to cancel arrears.
The statutes allow for this. Section 34(1)(f) of Ontario’s Family Law Act lets a court require that support be paid for any period before the order. Section 17 of the Divorce Act lets a court vary a support order retroactively. Which statute applies usually depends on whether the parents were married and divorcing. Parents who were never married, for instance, generally proceed under the Family Law Act.
The cases that set the framework
Three Supreme Court of Canada decisions do most of the work in this area.
D.B.S. v. S.R.G., 2006 SCC 37 is the starting point. It rejected the idea that a parent who is meeting the original order is safe from any later claim. It also set out the factors courts still use, which are discussed below, and it introduced what is often called the three-year rule.
Michel v. Graydon, 2020 SCC 24 is about a mother whose former partner had underreported his income for years. The Court allowed a retroactive increase under British Columbia’s legislation even though the child was by then an adult and the earlier order had ended. The reasons discuss, frankly, how underreporting and delay affect children and the parents who raise them, and they caution against penalizing a parent for not bringing a claim sooner when there may be good reasons for that.
Colucci v. Colucci, 2021 SCC 24 deals with the other direction, a payor who wants past amounts lowered. It sets out a framework that places heavy emphasis on notice and full financial disclosure. The father in that case had never told the mother about a drop in his income or sought a change for many years, and he was required to pay the approximately $170,000 owed.
Notice: the date that matters most
A key concept is effective notice, which means the point where one parent raises the possibility that support needs to be paid or changed. It does not require a lawyer, and it does not require a court filing. A clear text message or email saying “your income has gone up, and support needs to be recalculated” can be enough to start the conversation. You do not need to have proved anything by then.
Formal notice is different. It generally means starting a court application or motion, or otherwise taking formal legal steps.
Under the approach from D.B.S. as refined in Colucci, the starting presumption is that a retroactive change runs back to the date of effective notice, and generally no more than three years before formal notice. Three years is a guide rather than an absolute ceiling. A payor who hid income or otherwise behaved in a blameworthy way may be ordered to pay from the date the circumstances changed, even if that is further back.
Two practical lessons follow. First, if you suspect that the amount should have changed, say so in writing and keep a copy. Second, do not then sit on it. Effective notice loses its force if a long period passes with no real follow-up. In the hypothetical family above, a single email five years ago followed by silence is much weaker than an email followed by a request for tax returns, a reminder, and an application within a reasonable time.
The four factors a court weighs
Once the presumptive date is identified, a court can move away from it if that would be unfair. The factors are:
The recipient’s reason for delay. Understandable reasons might include fear of the other parent, lack of money for a lawyer, a child’s illness, or being misled about income. A parent who knew the facts and chose not to act for no real reason may get less sympathy. Courts are aware, though, that many parents have good reasons for not rushing to court.
The payor’s conduct. This is often the decisive factor. Blameworthy conduct includes hiding income, ignoring a disclosure obligation, pressuring the other parent not to apply and misleading them about finances. It need not be dramatic. Simply failing to tell the other parent about a substantial raise can count, especially if an order or agreement required annual disclosure.
The child’s circumstances. Did the child go without because support was low? Courts consider what the child’s situation was, and what it is now. A child who lived in real hardship while the payor did well presents a very different case from one whose needs were fully met. Hardship in the past is not necessary, however, because the money is an entitlement of the child.
Hardship to the payor. A large lump sum can be crushing, especially for someone with a second family or modest savings. A court can address this by spreading out payments, or reducing the retroactive period if necessary. Hardship has less weight if the payor created the problem by concealing income.
No single factor is decisive. They are considered together.
When the child has already grown up
Parents sometimes assume the door closes the day a child turns 18 or finishes school. Michel shows that this is not necessarily so. A court there varied an order even though the child had become an adult.
There is a legal nuance. Michel was decided under B.C. legislation, and the Divorce Act raises a slightly different question. In D.B.S., the Court said an original application under the Act generally requires that the person be a “child of the marriage” when the application is made, whereas a variation of an existing order is treated differently. Ontario’s legislation has its own wording. So a parent with an older or grown child should not assume either result, and should get advice about the specific route, the existing documents and how the delay can be explained. Delay itself is one of the factors, so an old claim still has work to do.
From the payor’s side
If you pay support, the most important protection is simple: be open. If your income rises, check your order or agreement for annual disclosure obligations, and share your tax documents as required. Adjust the amount in line with the Child Support Guidelines, and document it. Doing this avoids a large surprise later, and reduces the risk of being described as blameworthy.
If your income falls, do not just pay less. Tell the other parent quickly, and in writing, provide your proof, and take formal steps within a reasonable time. Colucci makes it clear that a payor who proves a past income drop is not automatically entitled to a matching decrease. Without notice and proper disclosure, the court may not go back very far, if at all. Cancelling existing arrears because you cannot pay them is even harder. The Court described it as a last resort, available in exceptional cases, and a payor generally has to prove they cannot pay now or in the future, even with a flexible payment plan.
If a demand arrives for past years, take it seriously, but do not assume the figure is correct. Check whether it uses the right table amount, the right income for each year and the right number of children, and whether it gives credit for money you did pay, such as direct payments or child care. Keep records, because undocumented cash is hard to prove several years later.
What you need to build or answer a claim
Retroactive support is calculated year by year, so the paperwork needs to go back too. A useful file usually contains:
- each parent’s tax returns and notices of assessment for each year in question, or as many as you can get
- any order, agreement or informal arrangement, and every written communication about money
- proof of what was actually paid, including e-transfers and bank statements
- records of where the child lived during each period, since a shift in parenting time may change the calculation
- the dates and content of any notice given
- records of special expenses like child care, orthodontics and activities, which may raise a separate claim for shared section 7 expenses
- for self-employed parents, business financial statements and expense records, since the income figure on a tax return may not reflect what is available for support
A working spreadsheet helps: one row for each year, showing the payor’s income, the table amount for that income, what was paid, and the difference. As a hypothetical, if the table amount should have been $650 a month and $400 was paid, the gap is $250 a month or $3,000 a year, and over three years that is $9,000 before any adjustments. Actual figures must come from the Guidelines tables in effect for each relevant period and from the real incomes. If you do not have the other parent’s income, the court process includes tools for requiring disclosure, and income can be imputed where a parent refuses to provide it.
Ways to resolve it
Most of these disputes do not have to go to trial. Once incomes are known, the math is often less contentious than people fear, and negotiation focuses on the start date and how payment will work. Common settlement terms include an agreed lump sum, payment in instalments, or a resolution that includes a change in the ongoing monthly amount. Keep in mind that a parent generally cannot bargain away a child’s right to adequate support, so an agreement should be reasonable and well-documented.
Where agreement is not possible, the path usually goes through the Superior Court of Justice or the Ontario Court of Justice, which both sit at 7755 Hurontario Street in Brampton. Which one depends on the type of case and any earlier order. A motion to change is used where an order already exists, while an application is used where there is none. The province’s online Child Support Service can set up or update amounts in certain straightforward situations, but it is not designed to resolve a contested claim about the past.
Starting sooner almost always helps both parents. If you are wondering whether a past year may become an issue, our page on child and spousal support gives more background, and you can contact the firm to discuss the specifics of your family’s timeline.