city shut off valve stuck
we've bought a new house that we're going to demolish in a few weeks. As part of the demolition permit, the city will come to turn the water off at the outside shutoff value at the property line. We've had to leave a large deposit with the city in case the valve is stuck so they can dig down and turn it off.
I've tried the valve, and it is stuck. I bet it hasn't been operated in decades. Darn. I couldn't try very hard because I don't have the special 5 sided socket to turn it, but my closest multi point socket indicates that it is seized. Perhaps frozen because the ground is frozen?
I know the actual valve is about 10' deep. Anything I can do so the it might actually work when the city shows up? Is it worth trying to dig down below the frost line. Would heating the valve stem help? Tapping it?
Thanks in advance.