Why is a cross-connection considered dangerous?

A cross-connection is considered dangerous primarily because it allows contaminants to flow into clean water. This can occur when there is a direct link between potable (clean) water and non-potable (dirty or contaminated) water. For example, if a hose connected to a garden faucet is submerged in a bucket of soapy water, a drop in water pressure can create a siphoning effect, pulling the contaminated water back into the clean water supply.

Therefore, the risk associated with cross-connections is significant, as it potentially exposes people to harmful pathogens and chemicals that could be present in the contaminated water. Ensuring that there are no cross-connections is crucial for maintaining safe drinking water and preventing waterborne illnesses.

The other options do not accurately describe the serious risk posed by cross-connections. Proper drainage and maintaining water pressure are important aspects of plumbing systems but do not directly relate to the dangers posed by cross-connections.