When a landlord’s property taxes are reduced by more than 2.49% from one year to the next, the rent also usually needs to be reduced. This is called an automatic rent reduction. When this happens, the city usually will send out a notice of rent reduction to the landlord and the tenants letting them know by how much the rent will be reduced starting January 1.
You do not have to get permission from your landlord to reduce the amount of rent you pay but you should speak to your landlord about it.
For more information, see the brochure: Automatic Rent Reductions and Tax Decreases.
Source: www.sjto.gov.on.ca