Fresh water Hose

Now let's take it a bit further....I put a new in line water filter on today too (one of those blue tube type). The label says it protects against bacteria and fungus and such. However there is a warning on the package flap that reads "do not use where water is microbiologically unsafe". Again if I'm using the hose everyday or very often fine. But now I'm thinking even if I drain the hose, as I always do, the inside of this filter will stay wet and after a couple of weeks of non use do the bad things grow inside the filter? I'm thinking I should only use these filters when I plan to use the hose every couple of days and give the hose and filter a good flushing before connecting to the RV.
Oh, we like to use the onboard water for everything. This is our third season of RVing and we haven't had a problem yet. I just unhook,drain,coil and couple (with the filter on.) No problem. Just had this thought.