RV Dump Stations Near Downs, KS
Concordia, KS is near great places to explore in an RV, and there are plenty of RV maintenance resources throughout the state. You can find free non-potable water at a large portion of these locations.
Here is the dump station in Concordia, but there are more spread throughout Kansas for you to keep an eye out for during your trip. There are a few storage businesses in the area that let you use their dump stations at no cost too. If you see an RV storage place, then you can probably dump your wastewater there as well.