Proper invoice

In Ontario construction, a proper invoice is the legal trigger for the prompt payment regime in Part I.1 of the Construction Act, R.S.O. 1990, c. C.30. Defined in section 6.1, it is a written bill or other request for payment for services or materials in respect of an improvement under a contract that contains every information element the section lists (plus any other requirements the contract specifies). Until one is given, the owner's payment clock does not start.

What it must contain

Section 6.1(1) requires the contractor's name and business address; the date of the invoice and the period, milestone or other payment entitlement it covers; identification of the contract or other authorization under which the payment is requested; the services or materials supplied; the amount payable; and contact details for the person to whom payment is to be sent. Subsection 7 lets the contract add requirements — which is why owners, including provincial ministries through their general conditions, spell out extra invoice content. The invoice must also meet "any other requirements that the contract specifies," but the contract cannot make payment conditional on a payment certifier's prior certification or the owner's prior approval (s. 6.3(2)), except for testing and commissioning (s. 6.3(4)).

What it triggers

Once the owner receives a proper invoice, s. 6.4 requires payment within 28 days unless the owner gives a notice of non-payment within 14 days identifying the amount not paid and the basis for it. Each level down the contracting pyramid then owes its subcontractors within 7 days of receiving payment. Interest runs on late amounts under s. 6.9 at the Courts of Justice Act rate, and unpaid disputes go to adjudication under the Act's ODACC regime.

The deeming and revision rules

An invoice that misses a required element is nonetheless deemed to be a proper invoice under s. 6.1(2) once the payer fails to give a notice of non-payment within the time allowed — defective paperwork cannot be used to stall the clock indefinitely. A proper invoice can only be revised after it is given if the owner agrees in advance, the invoice date does not change, and the revised invoice still meets the s. 6.1 requirements (s. 6.3(5)). Amendments in force January 1, 2026 revised several of the definition's information elements, so contracts and invoice templates drafted before that date need re-checking.

What it means for public-sector suppliers

On Ontario public construction, your payment date is engineered at invoice time, not at collection time. Submit monthly, complete, dated proper invoices; keep proof of the date the owner received each one; and diarize the 14-day non-payment window — if no notice arrives, the deemed-proper-invoice rule makes the amount enforceable on schedule regardless of paperwork defects.

Common questions

Is a proper invoice the same as a progress claim?

No. A progress claim is the contractor's valuation of work completed; the proper invoice is the statutory payment document that turns an entitlement into a running payment deadline. Many projects use both documents, with the invoice keyed to the agreed claim.

Does this apply to holdback?

The prompt payment rules run subject to the Act's holdback requirements (s. 6.2): the payer may withhold the statutory 10% holdback from each payment, but must still pay the balance on the proper-invoice schedule. See our retainage vs. holdback comparison.

Related definitions

Progress payment · Notice of suspension of work · Certificate of completion · Construction lien