The T4 is the Ontario Landlord and Tenant Board (LTB) application a tenant files when they signed an N10 Agreement to Increase the Rent Above the Guideline and the landlord did not deliver the capital work or new service promised in exchange. If the tenant succeeds, the LTB can declare the above-guideline part of the increase invalid from the start and order the landlord to repay it.
At a glance
| Who uses it | A tenant or former tenant who signed an N10 with the landlord |
| When | After the landlord failed to carry out the N10 undertaking |
| Notice period / deadline | Within two years after the agreed rent increase took effect |
| How it is served or filed | Filed by mail, courier, email or at ServiceOntario (not the Portal); the LTB serves the landlord |
| Filing fee | $53 |
| Follow-on form | Request to Review an Order (15 days) |
What the T4 is for
Section 121 of the Residential Tenancies Act, 2006 (RTA) lets a landlord and tenant agree to a rent increase above the guideline in exchange for a specified capital expenditure or a new or additional service. The agreement must be on the Board's N10 form, may not raise the rent by more than the guideline plus 3% of the previous lawful rent, can be cancelled by the tenant in writing within five days, and cannot take effect earlier than six days after it is signed (s. 121(2)–(5)).
Under s. 122(1), the tenant or former tenant may apply if the landlord:
- failed, in whole or in part, to carry out an undertaking in the agreement;
- based the agreement on work the landlord claimed to have done but did not do; or
- based it on services the landlord claimed to have provided but did not provide.
The LTB may find some or all of the increase above the guideline invalid from the day it took effect and order a rebate (s. 122(3)).
When to use it (and when not to)
The T4 only applies where an N10 was signed. An increase taken without any agreement, or one above what the guideline allows, is challenged with a T1. A service that was provided and later taken away is a T3 issue.
Deadlines and limitation periods
- Two years (s. 122(2)). No application may be made more than two years after the rent increase becomes effective. The clock runs from the effective date in the N10, not the date it was signed.
- Rent history. The form asks for two years of rent history, or from move-in if shorter.
How to fill out the T4, section by section
The form is version 01/04/2022.
- Part 1: General Information. Unit address, tenant names and contact details, landlord's name and address, related files.
- Part 2: Explanation of your application.
- The date the rent was increased and the amount of the increase above the guideline.
- A calculation: the allowed guideline increase compared with the agreed increase. The difference is the amount charged above the guideline.
- An explanation of which terms of the agreement the landlord did not meet.
- A two-year rent history.
- Part 3: Signature, then the accommodation and French-language request and the payment page.
Filing it
The T4 is not filed on the Tribunals Ontario Portal. The tenant files by mail or courier to the LTB at 15 Grosvenor Street, Toronto, in person at a ServiceOntario centre that accepts LTB documents, or by email to ltbpayments@ontario.ca, followed by a payment link that expires after three calendar days. The fee is $53.
If you are the landlord responding
- Pull the signed N10 and check the effective date. A T4 filed more than two years after that date is out of time.
- Prove performance. Invoices, permits, contractor sign-offs, dated photographs and completion notices for the capital work, or records showing the new service has been provided since the agreed date.
- Partial performance matters. The LTB may invalidate "some or all" of the increase, so show exactly what was done, even if not everything was.
- Check the calculation. Confirm the guideline rate for the year of the increase and that the agreed increase was within guideline plus 3%. If the agreed increase was too high, expect that part to be challenged as well.
- Disclose evidence at least 7 days before the hearing, or 5 days if replying (Rules 19.1–19.2).
Mistakes that get it refused, voided or dismissed
- Filed more than two years after the increase took effect. Barred by s. 122(2).
- No N10. Without an agreement under s. 121, the T4 is the wrong application.
- Only the guideline amount claimed. The T4 can recover only the portion above the guideline. The guideline increase itself is not affected.
- No explanation of the broken undertaking. The form requires the tenant to say which terms were not met.
- Wrong filing channel or no fee. The T4 is a mail, courier, ServiceOntario or email filing, and the fee must be paid.
What happens next
The LTB holds a hearing and issues an order. If the tenant succeeds, the order states how much of the increase is invalid and the rebate owed. A party may request a review within 15 days of an order issued on or after July 1, 2026, or appeal to the Divisional Court on a question of law within 30 days (s. 210).
Frequently asked questions
How much can an N10 increase be?
No more than the annual guideline plus 3% of the previous lawful rent (s. 121(3)).
Can the tenant back out of an N10?
Yes. The tenant may cancel by written notice within five days after signing, and the agreement cannot take effect sooner than six days after signing.
What does the tenant get if the T4 succeeds?
The LTB may declare all or part of the above-guideline portion invalid from the day it took effect and order the landlord to rebate what was overpaid.
Is there a deadline for the landlord to finish the work?
The N10 asks the parties to record the date the work was or will be completed, or the service provided. That date, and the details written on the N10, are what the LTB compares with what was actually delivered.