- If you need to dump your black or gray water while traveling near Concordia, Missouri, you'll find several options.- Pilot Flying J Travel Center and Missouri State Fair RV Park are two nearby locations where you can dispose of waste and fill up fresh water.- TA - Petro Stopping Center Oak Grove also offers a hose for flushing tanks along with trash bins for disposal.- Another option is Watkins Woolen Mill State Park which has a waste disposal station for RVers passing through the area.