It’s certainly one of the odder real estate misnomers.
So, “winterizing” a home doesn’t necessarily mean that it’s winter.
Rather, what it invariably means is that the home is: a) a bank-owned foreclosure; b) vacant; and c) therefore not being watched vigilantly.
To minimize carrying expenses and potential liability, banks will typically have the water shut off.
Of course, as the temperature dips, that also allows the bank to forego heating the home without the pipes bursting.
P.S.: How does a prospective Buyer tell if the plumbing in such a home works?
So, as part of each deal, they must negotiate with the bank owner over the logistics and associated expense of having the home’s water turned on, and then back off.