What device is used to prevent wastewater from contaminating potable water?

The air gap device is an effective method for preventing wastewater from contaminating potable water by creating a physical separation between the two. This device functions by ensuring that there is no direct connection between the water supply and the potential source of contamination. Typically, it consists of a vertical space between the top of a water outlet, such as a faucet, and the flood level of the receiving receptacle, like a sink or tank. This gap effectively eliminates the possibility of backflow, as even under pressure fluctuations or potential siphoning conditions, there is no way for contaminated water to reach the clean water supply.

In contrast, while other options like backflow preventers and check valves also serve important roles in protecting water quality, they do so by relying on mechanical functions that can occasionally fail if not properly maintained. A filter system can remove contaminants but doesn’t directly create a barrier to backflow like the air gap. Thus, the air gap device stands out as a simple, reliable, and passive solution to safeguard potable water from wastewater contamination.