RV Dump Stations Near Winchester, KS
Perry, KS is near some great places to explore in an RV, and there are plenty of RV maintenance resources throughout Kansas. You can find free non-potable water at Perry's dump station, and it's located at a scenic park. Topeka isn't far away, and has plenty of options for Kansas dump stations also.
There are a few storage businesses in Kansas 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.