On arrival Engine 16-3 found nothing showing. Command on location (1606) recalled all units with the exception of station 160. Dispatch was not able to contact a key holder and the alarm company could not reset the alarm remotely. Found unlocked window in the rear of the building and went inside to try to silence the alarm. Once inside found water leaking from the ceiling and running into the alarm system. Tried numerous time to contact owner or a manager. Shut off power to the whole building and drained the water from the system. Notified dispatch and cleared at 12:36pm