What does an air gap in a backflow prevention method achieve?

An air gap in a backflow prevention method is specifically designed to maintain a physical separation between the potable water supply and any potential contaminants. By creating this gap, it prevents backflow—where water from a non-potable source could flow back into the clean water supply due to a drop in pressure or other conditions. This physical barrier is critical in safeguarding public health and ensuring that drinking water remains uncontaminated by substances that might be present in wastewater or other less clean sources.

The effectiveness of an air gap in preventing cross-contamination is a fundamental principle in water safety practices, which makes it a crucial element in plumbing and water distribution systems. Having an air gap is one of the simplest and most effective methods of ensuring that the integrity of the drinking water supply is maintained.