Have to admit tcianci's is right, I am surprised no one has suggested changing the entire line to the street. The OP asked a simple repair remedy, and if he listens to all suggestions, he will be purchasing dry ice, he will be ripping out a brass valve and replacing it.....damn it is only a leak around a f**king valve stem which can be remedied in less then 5 minutes, with or without the valve being turned off, no need to make it a magillah.
This, gentlemen, is where I'm coming from. The man asked a simple question and all but a precious few actually read and understood it and fewer than them even knew what to do about it. The rest are indeed armchair plumbers, mechanics, carpenters or whatever hat they think they should be wearing today.
And as long as we're throwing around credentials:
Commonwealth of MA, unrestricted construction supervisors license CS-044337
Commonwealth of MA registered home improvement contractor registration 103463
In the trades for over 40 years now and spent a good portion of that working as a remodeler affiliated with a very successful local plumbing/heating/gas fitting company.
And I can read and comprehend questions and answer in a fashion that will lead to the resolution of rather than the creation of a problem.
Sorry guys, this ain't my first rodeo.
And, possibly further beating the dead horse, It's highly unlikely that the behaviors exhibited here would do any of you good in your day jobs unless misunderstanding simple questions and then digging yourselves into deeper **** by defending your ineptitude is a highly valued skill in todays workplace.