When you
buy a new home
Or opt for renting a place, you may not be acquainted with every single feature available. Thus, upon entering the kitchen, you could find yourself pondering “What is that gadget beside my tap?” When you press it, nothing happens—no soap emerges—and yet, unlike a spray nozzle, it doesn’t come off either. However, should you notice such an item attached to your kitchen sink, here’s what we know: It definitely qualifies as a
dishwasher
even if you haven’t utilized or even been aware of it so far.
This device is known as an air gap, a term that might seem odd for a dome-like metallic protrusion reminiscent of a miniature R2-D2. However, once you grasp its function, you’ll realize why the name fits perfectly. This article will clarify things for you.
What Is the Item Adjacent to My Faucet?
The air gap doesn’t belong to your faucet; instead, it’s an integral component of the sink drain, particularly within the dishwasher drainage setup. Its purpose serves dual functions: first, ensuring that the water expelled by the dishwasher post-wash and rinse cycle properly flows into the drain, and secondly, preventing reverse flow from the drain back into the dishwasher should the sink get blocked. If the
dishwasher drainage system
When you step away from it, the dishwasher might cease functioning. Even if it continues running, the backward flow could spoil your clean dishes. An air gap stops this contamination.
What Does Air Gap Mean?
Alex Atkinson, a California-based plumber, describes the air gap as follows: “It establishes a physical separation between the dishwasher and the drainage system. This ensures that if your sink becomes blocked and water begins to backup, it won’t be able to flow back into the dishwasher.”
If you examine it carefully, you’ll see that it features openings allowing both air and water to flow through (you might need to take off the domed cover to observe these). This is precisely why it’s referred to as an air gap.
What Is the Purpose of an Air Gap?
The dishwasher drain hose extends beneath the sink cabinet from the dishwasher to the sink drain, connecting to the drain tailpiece (or the
garbage disposal
If you have an air gap system installed, when the dishwasher initiates its drainage phase, a pump forces water through the discharge tube. As the water moves forward, it displaces a column of compressed air ahead of it. Under normal conditions, this pressurized air could potentially halt the flow of water, particularly if obstructions like debris enter the tubing and obstruct or partly block the opening leading to the sink drain. However, the presence of the air gap allows the trapped air to vent out instead of impeding the draining process.
Positioning the air gap either on the sink deck or the countertop necessitates two hoses: one ascending from the dishwasher up to the underside of the countertop, and another descending back down to the drain, thus creating a loop. The dishwasher pump generates sufficient pressure to push the water to the highest point of this loop; subsequently, gravity assists in channeling the water downwards towards the drainage system.
The air gap also safeguards the dishwasher against contamination from a
drain clog
When water moves backward from the drain toward the dishwasher, instead of flowing back into the appliance, it emerges through the air gap and spills over the countertop (which definitely indicates an issue). However, this prevents the water from entering the dishwasher hose. It’s almost as though it serves as a safety mechanism. As Atkinson clarifies: “Should your sink drain get blocked and water attempt to backup, it will exit via the air gap onto the counter surface without infiltrating the dishwasher hose.”
Is an Air Gap Necessary?
Depending on your location, the requirement varies, as noted by home repair specialist Kevin Crawford: “Air gaps may not be obligatory in every state. Certain regions permit something referred to as an
‘high loop’
Instead, you can mount the dishwasher drainage tube as high as feasible beneath the sink, often fastening it underneath the counter surface, then allowing it to loop downward towards the drain. While this approach offers some improvement over leaving things unaltered, it still falls short compared to using an air gap device.
As per Atkinson, states mandating air gaps typically adhere to the Universal Plumbing Code (UPC) which includes places like California, Washington, Hawaii, and Minnesota. In contrast, jurisdictions following the International Plumbing Code (IPC)—such as Florida and New York—are inclined to allow for the use of high loops instead. “Nevertheless,” adds Atkinson, “certain local regulations strictly demand a correct air gap installation. Therefore, when either renovating or setting up a new dishwasher, it’s crucial to verify with local guidelines.”
plumbing codes
or summon a plumber.”
About the Experts
-
Kevin Crawford
has more than two decades of expertise in luxury real estate. He serves as the co-owner of
TexFix
a business offering home repair and enhancement services in the regions around San Antonio, TX. -
Alex Atkinson
serves as both a plumber and an HVAC technician at
Super Brothers
, a plumbing and HVAC repair service based in Northern California.
