A limitation period is the deadline to sue. Miss it and the debt is real but unenforceable: the court will not hear you. For an unpaid invoice in most of Canada the basic period is 2 years, running from the day you knew or ought to have known the money was owed, which for a tradesperson is almost always the invoice due date. Quebec is the exception at 3 years under its own Civil Code regime, and the Atlantic provinces and territories run a longer 6-year clock. A written acknowledgement or a part-payment from the debtor before the clock runs out resets it to zero.
The basic period by province
The deadline to sue for a contract or invoice debt, by jurisdiction:
- Ontario: 2 years basic, 15-year ultimate cap (Limitations Act, 2002).
- British Columbia: 2 years basic, 15-year ultimate.
- Alberta: 2 years basic, 10-year ultimate.
- Saskatchewan, Manitoba, Nova Scotia, New Brunswick: 2 years basic, 15-year ultimate. (Manitoba's modern 2-year Act came into force on 30 September 2022; older claims followed a transition window.)
- Quebec: 3 years (the Civil Code calls this prescription, art 2925), with its own public-order rules.
- Newfoundland and Labrador: 6 years basic, with a 30-year ultimate cap.
- Prince Edward Island, Yukon: 6 years.
- Northwest Territories, Nunavut: 6 years. These older Acts are sometimes described as carrying a 30-year ultimate cap, but that figure is not confirmed, so confirm the territorial Act before relying on any ultimate period there.
Discoverability: when the clock starts
The nine modern common-law Acts (Ontario, BC, Alberta, Saskatchewan, Manitoba, Nova Scotia, New Brunswick) use a four-part discovery test. The clock starts when you know, or reasonably ought to know, that a loss occurred, that it was caused by an act or omission, that the defendant is responsible, and that a court proceeding is the appropriate remedy. For an unpaid invoice all four are usually true on the due date: you know the money is owed, who owes it, and that non-payment is your loss.
Quebec makes the same point directly: for unpaid services, prescription starts when the service was provided or the payment date passed. In the Atlantic provinces and territories that still use the older "cause of action arose" test (NL, PEI, Yukon, NWT, Nunavut), the clock simply starts on the due date, with no discoverability flexibility.
How acknowledgement or part-payment resets the clock
This is the lifeline for an old invoice. In every province and territory, a fresh written acknowledgement of the debt, or a part-payment, made by the debtor before the period expires, restarts the basic period from zero. The requirements are tight:
- The acknowledgement must be in writing and signed by the debtor. In most modern Acts an email or a text can qualify if it is signed in the broad electronic sense.
- A part-payment is treated as an acknowledgement of the whole debt.
- It must happen before the clock runs out. Once a claim is statute-barred, a later acknowledgement does not revive it.
Quebec works slightly differently. Under art 2898 of the Civil Code, the acknowledgement must be a clear and unequivocal recognition of the right. A vague offer to settle or a willingness to negotiate is not enough.
Worked example
You finish a job and invoice $9,000, due 30 June 2024. In Ontario your 2-year clock runs to 30 June 2026. In March 2025 the customer texts: "I know I owe you the $9,000, I will sort it next month." That signed written acknowledgement resets the clock: you now have until March 2027 to sue. Without it, miss 30 June 2026 and the debt becomes legally uncollectable, however genuine it is.
Common mistakes
- Letting an old invoice drift past the deadline. A real debt becomes worthless the day the period expires.
- Treating a chase as a reset. It is the debtor's written acknowledgement that resets the clock, not your reminder.
- Assuming Quebec is 2 years. It is 3 years, under a separate Civil Code regime.
- Relying on a vague "let's work something out" in Quebec. Art 2898 needs a clear, unequivocal acknowledgement.
- Confusing this with the lien clock. The limitation period is your long-stop; the lien deadline (often 60 days or less) is far shorter and runs separately (see Adjudication and Your Dispute Routes).
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