Can you double check the model number please as it doesn't seem to be coming up.
I have checked the model number again and I did get it wrong.
Model No. GC20C8C3EB
Serial No. 10743532SY Rev. 10
Ok thanks for that. Your model doesn't have a water filter built into the appliance im afraid.
So if you wanted a filter you need to get an external kit so the water filter will sit in line with the mains water supply feed to the appliance and you secure it to the wall. It comes as a full kit with instructions on how it goes.
Click here for the part
Hope this helps you but if you need anymore info just get back to me.