The process starts with an interest charge on the overdue balance and a registration against the title through Information Services Corporation, which puts any future buyer or lender on notice that taxes are owing on the property, calculated against a taxable assessment that is 80 percent of the property's assessed value.
If the arrears stay unpaid long enough, the City of Saskatoon can eventually initiate a tax sale under the Tax Enforcement Act, in which the property is sold to recover the outstanding taxes, but this is a last step reached only after a lengthy period of non-payment and notice, not an immediate consequence of one missed bill.
If back taxes are part of why you are considering a sale, resolving them before you list is almost always cleaner than letting a buyer's lawyer find them during a title search. Get your hand-reviewed valuation from Joel Dyck.