Since no faucets or toilet worked, I would guess the water line near the main hose connection from the city. If everything is working now, turn off the city water and pressurize the system with the pump then turn it off. Wait an hour without using any water. If you turn on the pump and it doesn't run, your probably OK. If the pump runs to pressurize the system again, you may have a leak. I can leave my system pressurized for several hours and the pump won't run when turned back on.
The upgraded insulation is not an absolute. It depends on outside temp and winds, how often the furnace runs, etc.