As KTMRFS mentioned, draining gray water into a large household bucket and manually dumping down a campground toilet is a decent option as well, discretely if you have to such as early or late in the day. I routinely run my faucets with the smallest trickle of water I can get, no thicker than wet spaghetti, and have fully adapted to that for everything -- hand washing, dishes, teeth brushing, etc. I could boondock parked for a month if I needed to with my three 40 gal fresh/gray/black trailer tanks, and have done so during Covid.
