What is defined as pesticide flowing back into the water supply?

The correct answer is defined as backflow, which specifically refers to the unintended reversal of the flow of water or other substances back into the water supply system. When pesticides are used, there is a risk that they can move from the intended application site back into the potable water supply through various means. Backflow can occur due to changes in pressure within the water system, leading contaminants like pesticides to enter the drinking water.

Understanding this concept is crucial in pesticide management and water safety, as it highlights the importance of implementing backflow prevention measures in agricultural practices and municipal water systems to protect the quality of drinking water. This is particularly essential for maintaining public health and environmental integrity. While terms like runoff, drainage, or leakage can relate to the movement of water or substances, they do not specifically address the scenario of pesticides entering the water supply system in reverse flow, which is precisely what backflow describes.