What does Ontario's Construction Act require of a contractor?
The Construction Act, R.S.O. 1990, c. C.30, is Ontario's payment and lien law. A proper invoice starts the clock: the owner has 14 days to give a notice of non-payment, and pays every amount it does not dispute within 28 days. Every payer retains a 10% holdback, an unpaid party can preserve a lien, and disputes go to adjudication.
The payment cycle, in order
- The contractor gives the owner a proper invoice, monthly unless the contract sets another cadence. A term that makes giving a proper invoice conditional on a payment certifier's prior certification or the owner's prior approval is of no force or effect (s 6.3(2)); certification or approval after the invoice is given, and testing and commissioning terms, are allowed (s 6.3(3), (4)).
- The owner has 7 days after receiving it to say in writing that it is deficient, or it is deemed a proper invoice. In force from 1 January 2026.
- Receive any notice of non-payment within 14 days after the owner receives a proper invoice, or the full amount is payable by day 28 (s 6.4(2), (3), 6.7; O. Reg. 303/18 s 3(a); O. Reg. 304/18 s 4). The owner may withhold only the amount a notice of non-payment specifies, and the notice must be in Form 1.1 (paper or electronic) and detail all of the reasons; every other amount stays due within 28 days (s 6.4(1), (3)).
- The contractor pays each subcontractor within 7 days of being paid, or within 35 days of giving the invoice if the owner has not paid, unless it gives the subcontractor its own notice of non-payment.
- Every payer retains a 10% holdback until the liens against it expire, and an unpaid party can preserve a lien or refer the dispute to adjudication.
Calendar days: the Act defines no business day. 'No later than N days after' an event excludes the day of the event (Legislation Act, 2006 s 89(5)), and a time limit ending on a holiday runs to the next day that is not one (s 89(1)); Sunday is a holiday there, Saturday is not.
What changed on 1 January 2026
The amendments in force on 1 January 2026 (Building Ontario For You Act (Budget Measures), 2024, Sched. 4) apply to every other improvement from that day (s 87.4(2)), except as s 87.4(3) to (7) provide: the annual holdback release starts later for a contract entered into before that day (s 87.4(4)).
Receive any written notice that an invoice is deficient within 7 days after the owner receives it, or the invoice is deemed a proper invoice
s 6.1(2), 6.3(6) · 7 days · no penalty stated
- In force from 1 January 2026.
Watch for the owner's notice of annual release of holdback, due within 14 days after each anniversary of the day the contract was entered into
s 26(2), (3), 87.4(4); O. Reg. 303/18 s 2(6); O. Reg. 304/18 s 1, 7 · 14 days · a breach of contract
- A duty on the owner, in force from 1 January 2026: Form 6, published on a construction trade news website (the Daily Commercial News, Link2Build or Ontario Construction News), stating the holdback it intends to pay and the payment date.
- For a contract entered into before 1 January 2026, the first anniversary that counts is the second one after that day, and that payment includes all holdback accrued before it (s 87.4(4)).
Be paid the holdback accrued in the contract year between 60 and 74 days after the owner publishes the notice of annual release, unless a lien is preserved and still standing
s 26(4), (7), (9), 87.4(4) · 74 days · a breach of contract
- In force from 1 January 2026.
Give any notice of adjudication within 90 days after the contract is completed, abandoned or terminated
s 13.5(1)-(3.1), (4), (5); O. Reg. 264/25 s 19 · 90 days · the claim is barred
- This text is in force from 1 January 2026; the earlier text was not read.
Pay any amount an adjudicator's determination requires within 15 days after it is communicated
s 13.15, 13.19(1)-(6), 13.20 · 15 days · a breach of contract
- 15 days from 1 January 2026 (2024, c. 20, Sched. 4, s. 23); the Act said 10 days before then.
Publish a notice of termination within 7 days after a contract is terminated
s 31(6)-(8), 87.4(6); O. Reg. 303/18 s 2(8); O. Reg. 304/18 s 1, 8 · 7 days · no penalty stated
- This text is in force from 1 January 2026 (Fighting Delays, Building Faster Act, 2025, Sched. 2, s. 6); the earlier s 31(6) and (7) continue for a notice published before that day (s 87.4(6)).
Every duty the library holds from the Act
In the order the library holds them. Each is on the Construction Act, R.S.O. 1990, c. C.30 (Ontario) page too, with how it was read.
| Duty | Window and section | If missed |
|---|---|---|
| Determine which version of the Act, and whether its prompt payment and adjudication Parts, govern the contract | none sets 1(4), 4, 5(1), 87.3(1), (4), 87.4; O. Reg. 304/18 s 13 | no penalty statedDisputes |
| Give the owner a proper invoice every month, unless the contract sets another cadence | 1 months 6.3(1)-(4) | no penalty statedDisputes |
| Make every invoice to the owner a proper invoice: contractor's name and address, date and period or milestone, the contract reference, a description of what was supplied, the amount and payment terms, and who is to be paid | none sets 6.1(1), 6.3(5), (6) | the claim is barredDisputes |
| Receive any written notice that an invoice is deficient within 7 days after the owner receives it, or the invoice is deemed a proper invoice | 7 dayss 6.1(2), 6.3(6) | no penalty statedDisputes |
| Receive any notice of non-payment within 14 days after the owner receives a proper invoice, or the full amount is payable by day 28 | 14 dayss 6.4(2), (3), 6.7; O. Reg. 303/18 s 3(a); O. Reg. 304/18 s 4 | you are liable for the full amountDisputes |
| Be paid every amount of a proper invoice that no notice of non-payment disputes within 28 days after the owner receives it | 28 dayss 6.2, 6.4(1), (3) | no penalty statedDisputes |
| Charge interest on any amount not paid when the Act makes it due, at the prejudgment interest rate or the contract rate if higher | none sets 6.9, 13.19(3), (4) | no penalty statedDisputes |
| Pay each subcontractor whose work was in a proper invoice within 7 days after receiving the owner's payment of it | 7 dayss 6.5(1)-(3), 6.6(1)-(3), (11) | a breach of contractDisputes |
| Pay each subcontractor within 35 days after giving the owner the proper invoice, even if the owner has not paid, unless a notice of non-payment is given | 35 dayss 6.5(4), 6.6(4), (5), (10) | a breach of contractDisputes |
| Give a subcontractor any notice of non-payment within 7 days after receiving the owner's notice of non-payment, or before day 35 after the invoice if the owner gave none | 7 dayss 6.5(5)-(8), 6.6(6)-(9); O. Reg. 303/18 s 3(b)-(e); O. Reg. 304/18 s 4 | you are liable for the full amountDisputes |
| Refer the owner's non-payment to adjudication within 21 days after giving a subcontractor a notice of non-payment that undertakes to do so | 21 dayss 6.5(5)(a)(iii), 6.6(6)(a)(iii) | no penalty statedDisputes |
| Give any notice of adjudication within 90 days after the contract is completed, abandoned or terminated | 90 dayss 13.5(1)-(3.1), (4), (5); O. Reg. 264/25 s 19 | the claim is barredDisputes |
| Give the other party a written notice of adjudication with the content the Act requires, and send a copy to the Authority the same day | none sets 13.7(1); O. Reg. 264/25 s 20 | no penalty statedDisputes |
| Ask the Authority to appoint a registry adjudicator if the agreed adjudicator has not consented within 4 days after the notice of adjudication | 4 dayss 13.9(2)-(6); O. Reg. 264/25 s 21, 22 | no penalty statedDisputes |
| Give the adjudicator the notice, and the adjudicator and the other party the contract and every document relied on, within 5 days after the adjudicator agrees or is appointed | 5 dayss 13.11; O. Reg. 264/25 s 24 | no penalty statedDisputes |
| Respond in writing to a notice of adjudication by the day the adjudicator specifies, copied to the adjudicator and every other party the same day | none sets 13.11.1; O. Reg. 264/25 s 25 | no penalty statedDisputes |
| Receive the adjudicator's written determination within 30 days after the adjudicator receives the documents | 30 dayss 13.13(1)-(6), 13.17.1; O. Reg. 264/25 s 30, 32 | a breach of contractDisputes |
| Pay any amount an adjudicator's determination requires within 15 days after it is communicated | 15 dayss 13.15, 13.19(1)-(6), 13.20 | a breach of contractDisputes |
| File any motion for leave to seek judicial review of a determination within 35 days after it is communicated | 35 dayss 13.12.1, 13.18(1)-(7) | the claim is barredDisputes |
| Answer a written request for contract or subcontract information within a reasonable time, not more than 21 days | 21 dayss 39(1)-(6) | damages onlyDisputes |
| Hold every amount owed or received on a contract or subcontract in trust for the subcontractors and suppliers owed, in a bank account in the trustee's name, with written records of every amount in and out | none sets 8(1), (2), 8.1, 10, 13 | a breach of contractLapsed compliance |
| Retain a holdback of 10% of the price of the services or materials as they are supplied, until every lien that may be claimed against it has expired or been discharged | none sets 22(1)-(4), 23, 24, 30 | you are liable for the full amountDisputes |
| Watch for the owner's notice of annual release of holdback, due within 14 days after each anniversary of the day the contract was entered into | 14 dayss 26(2), (3), 87.4(4); O. Reg. 303/18 s 2(6); O. Reg. 304/18 s 1, 7 | a breach of contractDisputes |
| Be paid the holdback accrued in the contract year between 60 and 74 days after the owner publishes the notice of annual release, unless a lien is preserved and still standing | 74 dayss 26(4), (7), (9), 87.4(4) | a breach of contractDisputes |
| Pay each subcontractor its accrued holdback within 14 days after receiving the matching holdback from the owner | 14 dayss 26(5)-(8) | a breach of contractDisputes |
| Be paid all remaining basic holdback within 14 days after every lien that may be claimed against it has expired or been discharged | 14 dayss 26(8) para 1, 27 | a breach of contractDisputes |
| Publish the certificate of substantial performance on a construction trade news website within 7 days of receiving the signed copy | 7 dayss 2(1), 32(1)-(4); O. Reg. 303/18 s 2(9); O. Reg. 304/18 s 1, 9 | no penalty statedDisputes |
| Preserve a lien within 60 days, by registering a claim for lien on title or, where the lien cannot attach to the premises, giving the owner a copy | 60 dayss 15, 16, 31(2)-(7), 34(1), (3)-(5); O. Reg. 304/18 s 11, 11.1 | the claim is barredMissed claims |
| Perfect a preserved lien within 90 days after the last day it could have been preserved, by starting an action and registering a certificate of action on title | 90 dayss 36(1)-(6) | the claim is barredMissed claims |
| Have the action that perfected a lien set down for trial, or an order for trial made, by the second anniversary of the action | 24 monthss 37(1), (2) | the claim is barredMissed claims |
| Publish a notice of termination within 7 days after a contract is terminated | 7 dayss 31(6)-(8), 87.4(6); O. Reg. 303/18 s 2(8); O. Reg. 304/18 s 1, 8 | no penalty statedMissed claims |
| On entering a public contract of CAD 500,000 or more, give the owner a labour and material payment bond and a performance bond, each covering at least 50% of the contract price | none sets 85.1(1)-(7), 85.2; O. Reg. 304/18 s 12, 12.1 | a breach of contractLapsed compliance |
In this guide
- Prompt paymentOntario prompt payment: the proper invoice, a deficiency notice within 7 days, notice of non-payment within 14 days, payment within 28 days, and interest.
- AdjudicationOntario construction adjudication: notice within 90 days of completion, documents within 5 days, determination within 30 days, payment within 15 days.
- Holdback, trust funds and bondsOntario's 10% construction holdback: who retains it, the annual release notice within 14 days of each anniversary, final release, trust funds and bonds.
- LiensOntario construction liens: preserve within 60 days, perfect within 90 days, set the action down for trial within 24 months, and substantial performance.
What this page is, and is not
It is the section text this library holds for Ontario's Construction Act, R.S.O. 1990, c. C.30 (Ontario), the Occupational Health and Safety Act, R.S.O. 1990, c. O.1 (Ontario) and Construction Projects, O. Reg. 213/91 (Ontario), with the window and the consequence. It is not legal advice, and it is not a substitute for reading the Acts, the regulations and the contract you signed.
Demiton does not yet track Ontario projects. These pages set out the duties; the product does not run these checks on an Ontario job today.
No library of law is complete, and Demiton never says this one is. An obligation the library does not hold, and you did not add, is not protected. You can add your own to any job.