Abstract: A unique piping arrangement of a water pump system is designed to prevent backflow of non-potable liquid into a potable water source thereby complying with plumbing codes to provide a safe cross connection. These codes are required when a water ejector uses pressurized potable water as an energy source. When the water ejector valve is open due to a high sump level and when the potable water pressure drops below atmospheric, the non-potable liquid can be siphoned into the potable water source thereby causing contamination, a significant unsafe health hazard to consumers. The present invention complies with plumbing codes by creating the required vertical air gap from the potable water source down to the non-potable liquid in the discharge piping as well as the inlet piping, the sources of contamination. In the piping arrangement are vents and drains to create the required air gap and transparent piping to provide required inspection and verification of proper operation.