I live in NYC and last night we had record breaker temperatures in the teens with minus wind. I have a gas boiler with a separate hot water tank. It’s a frame house semi detached with a crawl space. There is no hot or cold water upstairs but only cold water in the powder room but we have heat. We have under floor heating (recently installed) in the kitchen and powder room on the first floor which works with our current system, base board heating in the bedrooms and radiators in the living room. We just installed a whole house water filter system which is attached to the main water entry. Can someone please tell me why we are not getting water upstairs?

Pipes for the upstairs must be in an exterior wall and have frozen. If you have crawl space, where is boiler and water heater located?