You can bring your own hose to flush tanks at the RV dump station operated by the City of Altus. They provide both potable and non-potable rinse water. To get there, you need to go from Main Street to Falcon Road and turn east. Proceed two blocks east on Falcon Road, then turn north on an unmarked road that looks like an extension of North Jackson Street. Keep going for about 100 feet and take either the left fork of the Y intersection. Follow the road for another few hundred feet.