Wow, so many good replies! I'm sold then - although I do have a second non-potable water hose, I still hesitate to slap it on the fresh water feed at a campsite (not dump station). So I'm going to stick with a good grey water flush to get the chunks out, and just stow it with a tiny bit of sewer odor until it dries. That's what I've been doing and sounds like that's working out for a number of people.
I had to fill today at at spigot at a dump station itself. They had a white (ie. fresh water looking) hose hanging there. Ewww. No dedicated potable spigot, so I took off the hose, ran the spigot for a while and sprayed and swabbed it down with sanatizer, then used my clean water hose to fill tank. Hopefully that's enough because it starting to seem that dry camping, you don't have the luxury of always being too finicky.
