Part of the Ontario construction contracts guide for owners.
Ontario's construction adjudication system was designed to get money moving quickly. A contractor or subcontractor with a payment dispute can have a qualified adjudicator decide it in roughly six weeks, and the losing party has to pay while any longer fight carries on. For years it was seen mainly as a sub-trade's tool. That's changing: since January 1, 2026, the scope is wider, the window to start is longer, and owners are being drawn in more often, both as respondents and as claimants.
This guide explains how adjudication works under the Construction Act, what disputes qualify, the timelines, what a determination means for an owner, and how to be ready before a notice arrives.
What adjudication is, and who runs it
Adjudication is a fast, statutory process for resolving disputes on construction contracts and subcontracts. Any party to the contract can start it, including the owner. An adjudicator reviews the parties' documents, may hold a hearing, and issues a written determination.
The process is administered by Ontario Dispute Adjudication for Construction Contracts (ODACC), the Authorized Nominating Authority under the Act. ODACC trains and certifies adjudicators, keeps the registry of who can act, appoints an adjudicator when the parties can't agree on one, and certifies determinations. It doesn't decide whether a dispute can properly be adjudicated; that's for the adjudicator.
Since 2026, parties can also retain an ODACC-qualified private adjudicator by written agreement, at a fee of at least $1,000 an hour. Most disputes will still go through the registry.
What disputes qualify
Before 2026, the Act listed the matters that could be adjudicated: the valuation of services or materials; payment under the contract, including change orders and proposed change orders; set-off amounts; payment or non-payment of holdback; and any other matter the parties agreed to.
The 2026 amendments replaced that list with "any prescribed matter" or any matter the parties agree to. The prescribed matters are set out in Ontario Regulation 264/25, and law-firm summaries describe them as reaching broader contract performance issues such as scope of work, changes to the contract price and requests for extensions of time. For owners, that means a dispute over a delay claim or a disputed change order is now more likely to land in adjudication.
The ODACC data show what parties actually bring. In its fiscal year ending July 31, 2025, payment under the contract, including change orders, accounted for half of all determinations, and valuation disputes for about a third.
View the data
| Dispute type | Determinations |
|---|---|
| Payment incl. change orders | 72 |
| Valuation of services/materials | 47 |
| Notice of non-payment disputes | 9 |
| Non-payment of holdback | 6 |
| Other agreed matters | 6 |
| Holdback payment | 3 |
| Set-off amounts | 0 |
When adjudication can start
Under the old rules, a notice of adjudication had to be given before the contract was completed. Under the amended Act, it can be given up to 90 days after the contract is completed, abandoned or terminated, unless the parties agree otherwise. For subcontracts, the 90 days run from the earliest of completion, abandonment, termination, certification of the subcontract as complete, or the last supply of services or materials.
In practice, owners should expect claims to surface at or after closeout, when the contractor reconciles its final account. The end of a project is no longer a safe harbour.
The timeline
The process runs on short, fixed periods:
- Notice. The claimant gives the other party a written notice of adjudication describing the dispute and the relief sought, and proposes an adjudicator. A copy goes to ODACC.
- Adjudicator. The proposed adjudicator has four days to consent. If the parties can't agree or the adjudicator declines, ODACC appoints one within seven days of a request.
- Documents. The claimant has five days after the adjudicator is in place to deliver the notice, the contract or subcontract and the documents it relies on.
- Response. The respondent replies by the date the adjudicator sets.
- Determination. The adjudicator must decide within 30 days after receiving the claimant's documents. With the parties' consent, that can be extended by up to 14 days.
- Payment. Under the amended Act, an amount ordered is payable within 15 days after the determination is communicated to the parties.
View the data
| Step | Starts (day) | Maximum duration |
|---|---|---|
| Adjudicator consents | 0 | 4 days |
| ODACC appoints | 4 | 7 days |
| Claimant's documents | 11 | 5 days |
| Determination | 16 | 30 days (+14 by consent) |
| Payment of award | 46 | 15 days |
The respondent's practical window is short. If you receive a notice on a Friday, the claimant's documents may arrive the following week and the response date may be days after that. ODACC's pre-designed written processes limit each party's argument to between 2 and 25 pages depending on the process, so preparation is about evidence and clarity, not volume.
Interim binding: what a determination means
A determination is binding on an interim basis. The parties must comply with it, and it can be enforced through the court, but it isn't final. Either party can later take the same issue to court or arbitration, or the parties can settle it, and the later outcome doesn't depend on what the adjudicator decided.
The practical consequence for owners is that "pay now, argue later" is real. If an adjudicator orders you to pay a disputed change order, you pay within the statutory period, then decide whether the amount is worth pursuing further. Judicial review is available only in narrow circumstances, and the determination stays in force while a review is pending unless the court orders otherwise. Objections to the adjudicator's jurisdiction have to be raised as soon as the issue comes up, not saved for later.
Not every adjudication gets to a determination. Of the 324 started in ODACC's 2025 fiscal year, 116 were terminated, most often because the parties settled or resolved the dispute some other way, and 11 for lack of jurisdiction. A well-documented response often brings the claimant to the table before the adjudicator decides. The statutory clock is also less rigid in practice than on paper: ODACC reports that 61% of determinations that year were made within the timeline set by the Act.
Related disputes can now be heard together. Under the amended Act, any party can seek to consolidate adjudications on the same improvement, subject to the adjudicators agreeing, where previously only contractors could require it. For an owner facing a contractor's claim that simply passes through a subcontractor's change requests, consolidation can avoid arguing the same facts twice and getting two inconsistent answers.
From January 1, 2027, ODACC will publish determinations for new adjudications, with identifying information removed on request. Over time that will make outcomes more predictable, and also make your contract practices more visible.
What it costs
Adjudication is cheap compared with litigation. Where the parties and adjudicator don't agree on a fee, ODACC's schedule applies: flat fees of $1,600 to $4,000 for claims under $50,000, and hourly rates from $300 to $850 for larger claims, rising with the amount claimed. For claims of $50,000 or more, the claimant also pays ODACC a $600 referral fee and the parties share a $120 certification fee, both plus HST. The parties normally split the adjudicator's fee equally. A lawyer is permitted but not required, although on anything significant an owner should have one. The adjudicator can award costs against a party whose conduct is frivolous, vexatious, an abuse of process or in bad faith.
The real cost is internal: the time of project managers, consultants and counsel pulling records together on a tight deadline. ODACC's 2025 report shows 324 adjudications started, a median claim of about $213,000 and a median award of about $74,000 where something was payable. Those are amounts worth defending properly.
How owners should prepare
Most adjudications are won or lost on documents that existed before the dispute started. On programs we've supported, the owners who handled adjudication well had three things in place:
- Clean payment records. Proper invoices logged on receipt, deficiency notices issued within seven days where an invoice wasn't proper, and notices of non-payment issued within 14 days with reasons. Our guide to Ontario prompt payment rules covers those steps.
- A disciplined change record. Every change request, quotation, review comment and decision in one place, with dates. See our guide to managing construction change orders.
- A schedule that supports delay positions. With time extensions now within scope, accepted baselines and contemporaneous updates are evidence. A schedule nobody maintained is evidence too, just not for you.
What owners should do
- Read your contract's adjudication terms. Check whether it adds agreed matters or procedures, and get legal advice before changing them in supplementary conditions.
- Name who responds to a notice. Decide in advance who receives a notice of adjudication, who calls counsel, and who assembles documents. Four- and five-day periods leave no time to work that out.
- Keep the record adjudication-ready. Invoices, notices, change documents and schedule updates should be retrievable in hours, not weeks.
- Use adjudication yourself where it fits. An owner can start an adjudication too, for example over a disputed set-off or overbilling. It's faster than waiting for a lawsuit.
- Budget for paying first. Treat a pending adjudication as a cash-flow risk in your forecast, because an adverse determination is payable within weeks.
The bottom line
Adjudication has become the default forum for Ontario construction payment disputes, and from 2026 it reaches further into delay, scope and closeout. It rewards whoever has the better records on day one. Owners who keep their invoices, notices and changes in order can treat a notice as a manageable event rather than an emergency.
Facing a notice of adjudication, or want your payment and change records checked before one arrives? Book a 30-minute call with Benjamin R. Consulting.
Sources: ODACC, home page; ODACC, Adjudication Process; ODACC, FAQs; ODACC, Schedule of Fees; ODACC, 2025 Annual Report; Ontario Bar Association, Key 2026 Amendments and Practical Implications (2026); McMillan LLP, New Year, New Rules: Ontario's Construction Act Amendments Are Here (2025); McCarthy Tétrault, Ontario Construction Act Changes: Adjudication (2024); Blakes, Amendments to Ontario's Construction Act Now in Force (2026); Mann Lawyers, Ontario Construction Act: the Interim Adjudication Regime (2021); Link2Build Ontario, A Layperson's Guide to the Construction Act (2019). This article is general information, not legal advice. Get legal advice on your contract and specific circumstances.