That's my guess. I would call the landlord, your taking business away from us plumber's....just kidding. Shut off the water supply at the valve, if no shut offs then turn it off at the meter (alert other tenants 1st) Remove the screw, handle and stem. Remove and replace the washer, and O ring. RE-install, making sure the cap thread gasket is in place. Turn on the water and check for leaks.