After adding 3-4 pints of water/day to the BSF it started getting too wet so I stopped temporarily. The amount of water needed will vary depending on ambient humidity, temp, colony size, etc.
Being a little wet didn't hurt the larvae, but the bin did start to smell a little alcoholic. It's not like rubbing alcohol in your eyes alcoholic, more like someone poured beer on your cornmuffin alcoholic. I can almost imagine what the BSF colony might be like if the feed has fermented enough to produce ethynol.