Tenant Broke the Lease Early? What Ontario Landlords Must Do Under the Duty to Mitigate

When a tenant walks out mid-lease, you can’t simply bill them for every remaining month. Here’s what the Residential Tenancies Act actually lets you recover.

I’m Arthur Zhao. In twelve years of real estate — a good chunk of it representing landlords — the question I hear most from owners is blunt: “My tenant left before the lease was up. Can I make them pay the rest?” The instinctive answer is yes. Ontario’s actual answer is: only if you did your part to limit the loss. This piece explains the duty to mitigate — the obligation landlords most often overlook, and the single line that decides how much you actually get back.

The instinct that quietly costs landlords money

Most owners read a signed 12-month lease as 12 months guaranteed. It isn’t. There are three very different ways a tenant leaves early, and only one of them is what this article is about:

1. A proper move-out — the tenant gives correct written notice (for a fixed term, at least 60 days before it ends) and leaves. No breach; you can’t claim any “remaining rent.”
2. A mutual agreement to end early — landlord and tenant both agree to end the tenancy and sign off on it. Consent, so there’s nothing to sue over.
3. A unilateral breach (this article) — no proper notice, no agreement; the tenant just goes. This is the only scenario where “can I collect the rest of the rent?” is a real question — and the answer is more nuanced than most landlords expect.

What the duty to mitigate actually says

Section 16 of the Residential Tenancies Act, 2006 (headed Minimizing losses) reads:

“When a landlord or a tenant becomes liable to pay any amount as a result of a breach of a tenancy agreement, the person entitled to claim the amount has a duty to take reasonable steps to minimize the person’s losses.”

In plain terms: the moment you have a right to claim, you also have an obligation to keep that loss as small as reasonably possible. For a broken lease, that means making genuine, reasonable efforts to re-rent the unit as soon as you can. You cannot leave it empty, do nothing, and then hand the former tenant a bill for the entire remaining term. At an LTB hearing, that claim gets cut down — or thrown out.

Proving “reasonable efforts”: build your evidence file

The duty is abstract; what the LTB looks at is concrete proof. The burden is on you, the landlord. Start these four the day the tenant confirms they’re leaving.

After you re-rent: what you can and can’t recover

Abandonment vs. a proper move-out — they aren’t the same

The LTB’s Interpretation Guideline on abandonment defines it as a unilateral act by the tenant to give up the tenancy and possession of the unit without properly giving notice of termination. The dividing line from a proper move-out is exactly that missing, correct notice.

Here’s the counter-intuitive part: under s.2(3), a unit is not considered abandoned if the tenant is not in arrears of rent — even if it’s been emptied out. In practice, “abandonment” as a legal status usually requires unpaid rent.

Once abandonment is established, a landlord may apply to the LTB to terminate under s.79, move to re-rent, or deal with property left behind under s.42.

Which LTB form: the L10

To collect from a tenant who has already moved out, you file Form L10 — Application to Collect Money a Former Tenant Owes. The essentials below are all per Tribunals Ontario’s official L10 instructions:

• Deadline: file within one year of the move-out date, or the LTB won’t hear it.
• Eligibility: only for tenants who moved out on or after September 1, 2021. If they left before that, the LTB has no jurisdiction and you’re off to Small Claims Court.
• Fee: $201 to file online (per Tribunals Ontario).
• Cap: per Tribunals Ontario, the LTB’s monetary limit is $50,000; anything above goes to a higher court.
• What you can claim: arrears, the post-termination vacancy loss, NSF charges, unpaid utilities, and damage — each still subject to the duty to mitigate.

The deposit and last month’s rent

Many landlords assume the deposit can be applied to arrears or repairs. In Ontario it can’t.

The only lawful deposit is last month’s rent (s.105), and it can only be applied to the rent for the final month of the tenancy — not to mid-lease arrears, not to damage (s.106). If a tenant abandons and the final month happens to be the one the deposit covers, it applies cleanly; but you can’t use it to plug a vacancy or a repair bill — those go through the L10. You also owe the tenant annual interest on that deposit at the rent-increase guideline rate, which gets reconciled at the end. A separate “damage deposit” is not legal in Ontario — collecting one breaks the Act.