Which term refers to the dilution or mixing of harmful substances with water?

The term that refers to the dilution or mixing of harmful substances with water is contamination. Contamination occurs when pollutants, such as chemicals or microorganisms, enter a water supply, leading to a degradation of water quality. It can happen through various means, including accidental spills, agricultural runoff, or during backflow events.

In the context of water systems, contamination is a critical concern because it poses significant health risks to individuals consuming or using the affected water. Understanding contamination is essential for implementing preventive measures and ensuring safe drinking water standards, which is a key focus in backflow prevention training.

The other terms relate to different concepts. Siphonage refers to the action or process of drawing liquid through a siphon, which might not necessarily involve harmful substances. A cross-connection is a physical connection between a potable water supply and a non-potable source, which can lead to contamination if backflow occurs. Filtration is a water treatment process used to remove impurities and does not refer to mixing or dilution of harmful substances.