When I was a kid, I remember someone telling me that in New York City that steam for heating was provided by a utility -- like water and electricity. This was the explanation of the steam vents that you see in the streets on cold days.
This morning, while driving in -4 degree (f) weather, I noticed that the storm sewer vents along County Farm were releasing condensed water vapor simply because there was warmish water down their.
So, now I wondering -- are there parts of New York City where a utility provides steam for heating many adjacent buildings, and releases the excess through vents on the street and sidewalk, or is this just the same effect I observed this morning in the Chicago Suburbs?