A payment dispute needs the right notice, from the right party, within the right window, with evidence of service.
Construction Act
Prompt-payment applicability depends on the contract and procurement transition rules, not just the date on an invoice. Check section 87.3. The rules changed again on 1 January 2026; use the applicable version.
The owner’s notice is Form 1.1. Different forms and timing apply further down the payment chain. See section 6.4 and O. Reg. 303/18.
Read the governing sourceThe explanation below is a cross-province introduction. This jurisdiction note does not make every general example a rule for this province. Read the original notices of non-payment guide for the shared explanation.
A notice is a specific legal step
A notice of non-payment explains the amount withheld and the reasons for withholding it under the governing payment regime. Some jurisdictions prescribe a form and the manner in which it must be given.
A phone call or an informal email may not satisfy those requirements. Conversely, a notice is not proof that the underlying position is correct: the dispute can remain open to adjudication or other proceedings.
Start with who owes whom
The owner’s notice and a contractor’s notice to a subcontractor are different obligations. Their windows can run from different events. An upstream notice is not automatically a valid downstream notice.
Ontario’s owner notice is Form 1.1 under O. Reg. 303/18. Other Ontario forms cover different circumstances in the chain. Alberta, Saskatchewan and Manitoba have their own requirements.
Keep the notice and its journey together
Preserve the complete notice, its attachments, the correct recipient, the delivery method and the evidence showing when it was given. A draft sitting in a folder is not the same as a served notice.
- Identify the amount being withheld.
- State the reasons required by the applicable rule.
- Check the correct form and recipient.
- Record the service event and keep the evidence.
When the window is close
Use the actual facts to check the window promptly. If time is short or a notice has already been given, seek qualified advice about its effect. This site does not produce or serve a notice and does not decide whether an existing notice is valid.
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These are general educational explanations, not advice on a specific contract. Check the version of the law that applies to your project. This edition has not been represented as independently reviewed by a lawyer.
OntarioConstruction Act, ss. 6.1–6.6 and 87.3Source register & editorial method