If you are flushing your RV black and gray water tanks or cleaning out a tote tank, then you have to use a separate hose so that you don't risk cross contamination with a drinking water hose. The Camco RhinoFLEX 25 ft gray water hose has a 5/8 in internal diameter, is made of durable PVC and is bright orange so that you don't mix it up with your drinking water hoses by accident. The ends are compatible with standard garden hose threads.