waterlines in NY/NE are always buried well below the frost line and come into the house from underground, as a rule they don’t freeze
we were -20 for almost three weeks some years ago and my waterline never froze
and it was prolly even colder/longer where metmom lived at the time
Even with the air temp at -20, the snowpack prevents the ground from getting that cold.
And if it snows before the ground freezes, it insulates the ground and prevents the freezing in the first place.
The real problem is when it gets that cold with no snowpack.
But even then, the pipes are buried below the frost line, like you said.