water under fridge

Hi, I’m having problems with my Ge bottom freezer fridge - model number gbe18bapbrww - Serial number MG302735V - type DB18. There is a build up of water in the evapourating tray and it spills over onto the floor every couple of weeks. I have to use a wet vac to suck up all the water from the tray. I keep having to do this every couple of weeks. Any suggestions as to why this is happening? Why is there so much water? Can it be fixed? and If so How? Other than this there are no other problems with the fridge…no water inside…it stays cool…small bit of frost/ice gathers on back of fridge part near the temp. setting dial. That could be because the seals on the doors are not in the best shape. Other than that it runs good. I tried to find a manual online for this fridge and couldn’t find one…not sure why that is…must be a strange model???:confused: