Under sections 131–132 of Ontario's Residential Tenancies Act, when a rental building's property taxes fall by 2.5% or more from one year to the next, the rents of sitting tenants are reduced automatically — no application, no hearing, no landlord consent. The City of Toronto checks roughly 120,000 rental addresses against tax rolls every year and publishes the results as open data. In most years only a small number qualify — 92 properties in 2025, because taxes mostly rose — but in years with broad assessment decreases, thousands of buildings do.
How the amount works
The reduction is a percentage of your rent, calculated from the tax decrease (tax is assumed to be about 20% of rent, so a 5% tax drop produces roughly a 1% rent reduction). The City's notice states the exact percentage for your building, effective December 31 of that year.
What to do
Check whether your address received a notice for the current year (the City's list is public), then apply the percentage to your rent starting from the effective date. If the landlord keeps charging the old amount, you can deduct the difference or file a T1 application with the LTB to recover it — up to a year back.