I am trying to decide if I really need to install an air gap. I'd like my counter free of this, but am happy to install a step down kit, and have this connection placed high under the counter to still provide a gap of air. I've heard that with some dishwashers you can get away with this. I am about to replace my plywood counters and am deciding the numbers of holes for the new one.Or should I still be cautious and have a traditional air gap installed above the counter in case of a back up etc.? Sue
Air gaps are normally installed to satisfy local codes. Don't get me wrong they (codes and air gaps) are a very good thing. As long as the valve is above the ultimate water level/top of the siphon it should perform the same function. I wouldn't think that all local inspectors would agree however. They would want to see the device in pain (oops plain) view. Also if the sink drain ever backs up higher then the placement you will/may have backup water on your floor or in your cabinets. can be a bit nasty although still probably safer the in your dishwasher but in the back of a cabinet it could go unnoticed and mold and stuff. I have been in many home that don't have them (air gap) at all. My self I had opened my dishwasher once and smelled a fowl smell. I fixed my drain blockage ran a empty load cycle and then rewashed the dished a few times on hottest setting. (none of the water came in contact but their was nasty on the bottom of the washer) I would of liked the air valve already in place. My ultimate opinion put the valve in the way it belongs (they don't really look that bad and what's another hole. other option that would also work is if you could run the valve up in another room or area if placement is good for drain routing. (my utility / mud room shares a wall with my kitchen gives me many options. Another possibly is to install a one way check valve in the line. This will help prevent backups as well and will not have to be at any height. Check valves in drains are however sometimes not 100% reliable due to solids sometimes hanging in and blocking the open slightly. Well I hope I gave you some good food for thought.