It is possible that the water pump is leaking, but with a vehicle with a lot of miles it could be an assortment of things. There is a "weep" hole on the bottom of the pump that would indicate a pump leak. Take a mirror and a light and look at the hole to see if any coolant is present. Anymore than a drop or two means it's time for a new pump.
ASE Master Technician, Lead Technician for Deutsch American Inc. Over 6 years of Import Service-specializing in German Automobiles.