What is a cross connection in plumbing?

A cross connection in plumbing refers specifically to an actual or potential tie between potable water and any source of pollution. This definition is critical because it highlights the health risks associated with cross connections. Such connections can lead to contamination of the drinking water supply if non-potable water, which may contain harmful impurities or pollutants, accidentally enters the potable water system. Plumbing codes and regulations emphasize preventing cross connections to ensure the safety and quality of drinking water, making proper identification and management of these connections essential for public health.

The other choices describe different plumbing concepts but do not pertain specifically to the definition of cross connections. A connection between two drainage systems does not imply a direct risk to potable water. A type of water filtration system relates to improving water quality rather than defining a connection. Lastly, a method of venting in drainage systems focuses on ensuring proper airflow in sewer systems and does not involve the concept of connecting different water sources. Therefore, understanding cross connections as a susceptibility for contamination reinforces the importance of safeguarding potable water lines against pollutants.