Every time I try filling up the fresh water tank I end up over filling it and then it spits water from the overflow for a while. I've tried looking through the access hole with a flash light which is a PITA. The other option is to keep the level button depressed until the full LED lights up...another PITA.
I decided to remove the black plastic cover and now I can watch the level as it fills.
While you are in there, If you are experiencing some chatter while your water pump is running take a look at how it is mounted. The motor part of the pump is mounted with some rubber brackets, which is fine. However, the pump part, at least on ours, hits the floor. It needs to be isolated.