shut off valve leak

This seems to happen to me all the time. I just bought an older home and have some work to do before I move in. i thought it would be a good idea to turn off the main water supply since I won't be back at the house for a week or so. When i turn the valve back on it now has a slow leak from the stem. Seems like any of the shut off valves that haven't been operated for years will start leaking if I turn them.

Not unusual. It is probably a gate valve with a bonnet nut. You could try tightening the nut just a little. Don't overdue it.

Unless it is a valve with an "O" ring seal, tightening the nut beneath the handle should stop the leak. Do not tighten too much or the handle will not turn.

Thanks, I tightened the nut and looks like it stopped.