Which device is used to prevent contamination of potable water?

• A. Pressure gauge
• B. Double check valve
• C. Atmospheric vacuum breaker
• D. Both double check valve and atmospheric vacuum breaker

Answer: (D)

The device used to prevent contamination of potable water is a combination of a double check valve and an atmospheric vacuum breaker. Both of these devices serve critical functions in maintaining the safety and quality of drinking water by preventing backflow.

A double check valve is particularly effective in areas where there is a potential for non-health hazard backflow. It consists of two independently acting check valves, which provide redundancy and reliability in stopping any backflow that might occur due to pressure changes in the water system.

An atmospheric vacuum breaker prevents back siphonage, a type of backflow that can occur when the pressure in the system drops significantly, creating a vacuum. This device allows air to enter the piping system, effectively breaking any potential siphoning action and thus preventing contaminants from entering the potable water supply.

Both devices are essential in protecting the potable water supply from potential contamination risks associated with backflow, which can carry pollutants and other undesirable substances back into the clean water system. Using them together enhances water safety and compliance with health regulations regarding potable water systems.