What is 'backflow' in the context of wastewater systems, and why is it dangerous?

Backflow refers specifically to the reversal of flow in a plumbing system, which can occur when there is a change in pressure within the system. This condition can lead to the unintended movement of wastewater or contaminated water into clean water sources, particularly drinking water supplies. This is dangerous because it can result in serious health risks due to the potential for pathogens or pollutants to mix with potable water. Proper backflow prevention measures are essential in municipal wastewater systems to protect public health and ensure the safety of drinking water.