Since damage to the pipes and to the road tends to be concurrent, they can repair one when they repair the other.
As for the meltwater, this is going to be a fairly small amount of hot water in a regional sense. Snow is fluffy, but it's about 10x less dense than in its liquid state; meaning that ten inches of snowmelt is the equivalent of only about an inch of rain. That's about 27,000 gallons per mile of roadway (a mile is about an acre) going into the storm sewers, which is more or less the same amount of water that a large building goes through in a day. But this snowmelt isn't a daily occurrence, it's only going to happen a few times a year.
I recognize that I just did a lot of handwaving, but the point is that, to within an order of magnitude, it's hundreds of times less impact than building another large office building (which cities do frequently).