Water leaking into HVAC

My wife and I just moved into this new place that we are renting through a property management company. We turned on the heat to find a river of water running through our floor vents and then quickly turned it off after hearing a large amount of water sloshing through the house. The leak that was causing that has been found, however you can still hear a small amount of water within the system. We are concerned about the mold that might have form/be forming after this occurred. Does anyone have any advice or recommendations on what steps to take next? Either with our leasing company, or steps we can take to mitigate the moisture this has caused.