Backflow Prevention Practice Exam

What preventive measure can be used to reduce the incidence of backsiphonage?

1. Diaphragm valve installation

2. Air gap maintenance

3. Increased water pressure

4. Use of non-return valves

The correct answer is: Air gap maintenance

The preventive measure that effectively reduces the incidence of backsiphonage is air gap maintenance. An air gap is a physical separation between the water supply and potential contaminants, ensuring that backflow cannot occur. This is particularly crucial in plumbing systems, as it prevents wastewater or other possibly contaminated water from siphoning back into the clean water supply. Maintaining a proper air gap requires ensuring that the height difference between the outlet of a water supply and the highest possible contaminant level is adequate. By doing this, any drop in water pressure that might cause backsiphonage will not lead to contamination, as air gaps are designed to keep the two sources distinctly separate. Other options do not address backsiphonage as effectively. For instance, while diaphragm valves and non-return valves can prevent backflow, they are not specifically designed to deal with backsiphonage and may not always be reliable in all scenarios. Increased water pressure could actually exacerbate the problem by pushing contaminants into the clean water supply if not managed properly. Thus, air gap maintenance stands out as the preferred method to control backsiphonage.