Does a Dishwasher require a Air Gap?

[Christopher Currins]

http://www.nachi.org/forum/f22/dishw...rain-line-838/

[Scott F. Coslett]

It appears that we are confusing an air gap with waste water venting .
An air gap is used at the end of fresh water supply or the potable water supply to prevent siphoning back . Such as at the end of your tap to sink . At least I thought it used to mean that . But they are two separate issues .

Allan I believe you are refering to backflow preventer or a vacuum breaker.

I recommend installing an air gap fixture or having the drain line in a 'high loop' configuration attached to the underside of the countertop. Many newer washers have a high loop feature already configured on the back of the machine, however I still make the recommendation.

[agallatin]

You made a valid point Jeffrey . A dishwasher is a little different situation . The water enters the tub at the bottom and the drain is of course at the bottom . The only real air gap in this situation is when the tub is pumped empty , the tub being the air gap . You still after pump out have waste water in the pump and hose below the waste water drain line . It would make sense to have a check valve to prevent any drain back to the dishwasher tub . Though it is no a requirement in our area . There is also no requirement for a vent system in this area .

[Tim Spargo]

Some manu's (so I'm told) have prevention built in... likely due to the above confusion , as mentioned, here in CA if it doesn't have an air gap, it's wrong.

These fittings are cute, I think I've yet to find someone that used a fitting like this *with* and air gap.