Can a Lender Start Power of Sale Right After One Missed Payment in Ontario?

Not right away: where the mortgage has a power of sale, the lender cannot give notice of exercising it until the default has continued for at least 15 days. It then cannot sell until at least 35 days after the notice is given.

The 35-day notice must go to every person having an interest in the property. It must be in Form 1, Notice of Sale under Mortgage. If your mortgage has no power of sale clause, the statutory power applies only after three months' default and requires 45 days' notice. Whether a single missed payment is a default, and what else the mortgage requires, depends on its own terms, so read the document carefully.

Once notice is given, the lender cannot start any further proceeding to enforce the mortgage until the time stated in the notice has passed unless a Superior Court judge permits it. Before the sale closes, paying the arrears and necessary expenses can stop acceleration enforcement; afterwards you can only claim damages. Interest on arrears cannot be charged at a rate higher than the mortgage rate. If you miss a payment, contact the lender early and get advice before the notice period runs.