In order to get the water to come out the 3" sewer pipe you will still need to open the valves using the motorized boxes in the sani-con compartment. What really happens when you open a valve the water runs into the 3" pipe and the sani-con pumps it from this pipe. If you don't want to use the sani-con, hookup a hose to the end of the 3" pipe and open the valve, after placing the other end in the sewer hole.