Yes, and in Toronto it is substantial. The City's Basement Flooding Protection Subsidy Program covers up to 80% of invoiced cost, to a maximum of $1,600 per backwater valve (up to two), $2,250 for a sump pump plus $300 for a battery backup, and $400 for pipe severance and capping — up to $6,650 per property in total.
The conditions catch people out. Your eavestrough downspouts must be disconnected from the City sewer, the contractor needs a valid Toronto business licence, a building permit is required for a backwater valve, and the valve must not be covered before the inspection. Applications run first-come first-served against annual Council funding, and you have two years from installation to apply. Several other GTA municipalities run their own programs on different terms — we check yours before quoting.