How Do I Use My Water System? 1996 Winnie Brave

It's almost impossible to tell without a picture and just description, but water shouldn't be draining out of your RV unless you want it to. Play with the value leading up to it to see if it stops it by flipping to the other position. It's possible this valve may be broken. Your water pump will always run because it's never building pressure if it keeps draining and your water supply certainly won't last long.