What is a common cause of disease due to cross-connections?

Cross-connections occur when there is a direct physical link between a public water supply and any source of contamination, which can lead to various health risks. A common cause of disease linked to cross-connections is backflow, which can introduce harmful substances into the potable water supply.

Back-siphonage of contaminated chemicals refers to the situation where reduced pressure in the water supply can draw chemicals from a nearby source into the drinking water. This typically occurs due to a drop in pressure, such as when there is a water main break or heavy demand on the system.

Backflow of biologically contaminated liquids occurs when non-potable water flows back into the drinkable supply. For example, if there is a non-potable source like a swimming pool or industrial water that accidentally connects to the potable supply, any pressure change could lead to backflow, introducing pathogens into the drinking water.

The connection of the water supply to the sewer system creates a significant risk; if there's a failure or pressure drop in the sewer system, sewage can be siphoned back into the drinking water supply, causing severe health risks due to the presence of harmful pathogens.

By recognizing that any of these conditions can directly lead to cross-connections and result in the contamination of drinking water, it