What type of connections pose a significant risk for backflow?

Unprotected cross-connections that involve chemicals or hazardous substances are considered to pose a significant risk for backflow because they can facilitate the introduction of contaminants into the drinking water supply. When such substances are inadvertently drawn back into the drinking water system due to backpressure or back-siphonage, it can lead to serious health risks for consumers.

The lack of protection, such as backflow prevention devices, in these scenarios allows for the possibility of harmful chemicals—such as pesticides, fertilizers, or industrial substances—to mix with potable water. This contamination can happen even with relatively small changes in pressure within the plumbing system, making it essential to identify and manage these high-risk connections appropriately.

In contrast, connections that are secured with proper barriers are designed to prevent backflow, and connections involving only water (assuming they are not contaminated) generally present a much lower risk. Connections between potable and non-potable water sources also carry a risk, but the presence of hazardous substances dramatically increases the potential for serious contamination incidents.