When potable water is discharged into any reservoir, air gaps are essential to:

• A. Prevent backsiphonage
• B. Provide additional oxygen
• C. Maintain pressure
• D. Aid in collecting condensates

Answer: (A)

Air gaps are used to prevent backsiphonage, which is the siphoning of water from a non-potable source back into the potable supply. When potable water is discharged into a reservoir, a drop in pressure downstream can pull contaminated water backward through the connection. An air gap provides a physical break between the clean water line and the reservoir, so even if pressure changes occur, there’s no path for contaminated water to be drawn back into the supply.

The other options don’t fit this purpose: air gaps don’t add oxygen to water, they don’t actively maintain system pressure, and they aren’t designed to collect condensates.