What is the term for the vertical empty space that prevents cross-contamination between a drinking water supply and an unapproved water source?

The term for the vertical empty space that prevents cross-contamination between a drinking water supply and an unapproved water source is known as an air gap. This is a critical concept in water safety and distribution because the air gap creates a physical barrier that ensures no direct connection between the potable water supply and potential contaminants from non-potable sources.

An air gap is typically established by ensuring that the outlet of a water supply pipe is positioned above the level of the highest possible contamination source. This gap prevents any backflow or back-siphonage, which could occur if there were a pressure change within the system, leading to the contamination of the drinking water with harmful substances from the unapproved source.

Understanding the importance of an air gap is essential for water operators as it helps maintain public health and complies with regulatory standards regarding water quality and safety.