[flybouy]

Originally Posted by CedarCreekWoody

That flush valve is actually an anti-syphon valve. It is on the Line to the sprayer inside the black tank. If your tank is empty you do not need to add any water to the tank. Just open the drain valve, connect the flush line, and let the water drain out on the ground as it will only the clean water you are spraying (assuming you have a clean tank.)

I would never recommend dumping black water on the ground. While it may look "clean" it isn't sanitized. Nothing carries more diseases than fecal matter. It doesn't take much.