The Lakeshore towns, and the oldest services in Etobicoke
Mimico, New Toronto and Long Branch were built as their own municipalities before the war.
Factory housing went up on the numbered streets in New Toronto, foursquares through south-central Mimico, and 1 1/2-storey bungalows across the interwar years. Anything built before the mid-1950s can still have a lead water service on the private side, and this is the part of Etobicoke where that is genuinely likely.
Galvanized supply is common here too. Galvanized does not announce itself by leaking; it scales inward until the shower runs thin while the kitchen tap seems fine. If the front yard is already open, that is the moment to deal with the whole service.