A dishwasher air gap is a small, cylindrical device mounted on your kitchen sink or countertop that prevents dirty water from flowing back into your dishwasher. It’s an essential part of many plumbing codes and helps keep your dishwasher’s water supply clean.
📍 Best Placement for an Air Gap
✅ On the Sink or Countertop – The air gap is typically installed next to the kitchen faucet, on the back edge of the sink or countertop.
✅ Near the Dishwasher – It should be positioned as close as possible to the dishwasher and drain line for optimal performance.
✅ Above the Sink Drain Level – The air gap must be higher than the sink drain to function properly and prevent backflow.
🔧 How to Install a Dishwasher Air Gap
1️⃣ Drill a Hole (If Needed) – If your sink or countertop doesn’t already have an extra hole, you may need to drill one (typically 1-3/8 inches in diameter).
2️⃣ Insert the Air Gap – Place the air gap into the hole and secure it with a mounting nut underneath.
3️⃣ Connect the Hoses:
- One hose connects from the dishwasher drain outlet to the air gap inlet.
- Another hose connects from the air gap outlet to the garbage disposal or sink drain.
4️⃣ Secure and Test – Tighten all connections, turn on the dishwasher, and check for leaks or drainage issues.
🚫 Do You Need an Air Gap?
- Required by Code in some areas (especially in the U.S.).
- Alternative: If local codes don’t require an air gap, you can use a high loop method (looping the drain hose under the sink as high as possible).
Final Thoughts
If your local plumbing code requires an air gap, install it on the sink or countertop next to the faucet. If an air gap isn’t required, you can opt for the high loop method instead.