Back-siphoning is the reverse flow of liquid into which component?

• A. A fill hose
• B. A return line to the tank from the sprayer
• C. A drain in the ground
• D. A portable water bottle

Answer: (A)

Back-siphoning happens when liquid is drawn backward into the supply line, typically through the fill hose that brings liquid from a water source into the sprayer. If pressure in the source drops or a suction effect occurs, liquid can be siphoned up the fill hose and contaminate the water source or container. Because the fill hose is the direct conduit between the water source and the sprayer, it is the component at risk of receiving this reverse flow. That’s why anti-siphon or backflow prevention devices are required on fill connections. The other components listed aren’t the path for reverse flow in this context: a return line stays within the system, a drain in the ground isn’t the reverse-flow path into a component, and a portable water bottle isn’t part of the typical pesticide application setup.