Since I'm hoping to start washing my dishes outside (in a double bucket--suds on one side/rinse on the other) I was wondering is it permissible to let the water drain on the ground, or is that a no-no?
I see nothing wrong with throwing your rinse water out under a plant but most parks have waste water dump sites. As far as the wash water, I know that I have pulled into some campsites where washwater was dumped and it was no fun to have noodles all over the ground where they just dumped their bucket. Left over food becomes very gross after a day or so on the ground. Some campgrounds discourage dumping waste water on the ground and some say they will even fine you, so use caution if you plan to dump on the ground instead of in waste dump sites.
If the campground doesn't have a grey water disposal spot, then you can dump it in the outhouse. That's what I usually do since we camp where there are lots of bears and don't want to dump wash water in or near the campsite.