I was literally just wondering that, too. In NYC, for instance, there are a number of places [1] that are considered "destination chargers" that are parking garages throughout the city. I imagine that for an add-on fee to the monthly rental of a parking space, they also providing charging. That being said, I imagine it easily puts the potential monthly parking fee near $1,000.00 a month (given that it looks like indoor garage parking is generally around $600 - $700 a month.)
[1] https://www.teslamotors.com/findus#/bounds/43.02971601884381...