Question about Air Gaps

[Steven Schuster]

Does anyone in the area know if air gaps are required to be connected to drainage pipe from dishwasher to garbage disposal? I recently had some plumbing work done under the sink, but there is no air gap connected to that drainage line. My contractor is saying I don't need it. But everything I'm reading says that it's code in a lot of places, and a really good idea, even if not required. Anybody have any insight on this?

[Christopher Phillips]

@Steven Schuster

Not "really" needed, per se. 

However, SECTION 409 DISHWASHING MACHINES, of the Texas plumbing code states Air Gaps are required and need to be inspected annually.

The concern is waste backing up into the water supply if the water pressure dropped during water supply disruptions.