Believe it or not, whatever goes into your bathroom in your RV doesn't disappear into thin air. The waste ends up in your RV's septic system, and that system eventually gets full. If this were to happen in the middle of a trip, what would you do? Well, if you have a portable waste tank then it shouldn't be a problem. The device will save you a lot of time and effort, especially if moving your RV to empty the tank will be a hassle.