What is back-siphoning?

Back-siphoning refers to the phenomenon where liquids, such as pesticides, are drawn back into the water supply due to a pressure change. When a system’s pressure drops, it creates a vacuum that can pull pesticides from a sprayer or tank back into the source of the water supply, which can lead to contamination of potable water. This process is a significant concern as it poses risks to public health and the environment, highlighting the importance of employing proper backflow prevention measures when handling pesticides.

The other options do not accurately describe back-siphoning. The prevention of pesticide drift relates to minimizing the spread of pesticide particles away from the target area during application. Mixing of pesticides in tanks is a standard procedure for preparing a solution for application but does not involve the reverse flow into a water supply. Dilution of pesticides is about reducing concentration with additional liquid, which does not imply any backflow into the water system.