Dishwasher Air Gap Leaking: How To Repair3 min read

Leaks in the kitchen are never enjoyable, but we all have to face them from time to time. One such leak that you may encounter is with the dishwasher air gap, which connects your kitchen sink to your dishwasher. So, how do you fix an air gap leak?

Dishwasher air gap leaks are typically caused by debris, kinks in the tube, or issues with a garbage disposal. Remove the fitting and look for any blockages. You can use a snake or vacuum to remove large debris. You can also remove the knock-out insert in your garbage disposal if necessary.

Don’t panic if you have a leak in your air gap. This issue is pretty common and straightforward to resolve. Let’s take a closer look at everything you need to know to fix the problem as soon as possible.

What Is an Air Gap?

An air gap (example on Amazon) might sound like an issue, but it’s either built into the dishwasher or required by local plumbing codes.

The dishwasher air gap consists of a small cylinder fitting that links the kitchen sink drain to the dishwasher. It basically prevents dirty water from coming into contact with clean dishes, and it stops water from running out in a cleaning cycle.

The simple tool ensures your dishes are clean and don’t come into contact with contaminated water.

Note: Dishwasher air gaps are required in most states. My dishwasher doesn’t actually have one, as it was installed before the law was instated, so this article is based on thorough research and prior knowledge of how to fix the leak.

Dishwasher Air Gap Leaking

How Does an Air Gap Function With a Dishwasher?

The dishwasher air gap is a small fitting that typically sits about two inches above the sink. It functions by separating two sections of the hose with an unpressurized gap of air. One area of the tool links to the dishwasher, while the other attaches to the garbage disposal.

Dirty water is pumped into the air gap via the first hose and released into the drains via the second hose. This design prevents backflow, which happens when contaminated water re-enters the dishwasher. It provides similar benefits to air vents in sinks (another article I wrote).

4 common causes of an Air Gap Leak

The air gap is surprisingly simple and elegant, but that’s not to say it can’t encounter issues. There are a few different causes for air gap leaks, including the following:

1. Debris Buildup

The most common culprit behind an air gap leak is a blockage from food waste, grease, and other debris. Jams typically occur in the hose when there’s less pressure to move wastewater and particles.

Significant blockages will cause water to back up and spill into the sink basin.

2. Kinks in the Hose 

In some cases, leaks can happen from kinks in the tube or hose. This issue is similar to debris buildup, as it causes water to back up and overflow into the sink.

3. Issues With the Garbage Disposal

Underlying problems with a garbage disposal can also cause leaks in the air gap. That said, you’ll typically notice major blocks with the garbage disposal before the air gap begins to leak.

4. No Knock-Out Plug

If the water constantly leaks from the air gap when your dishwasher is draining, you may have issues with your knock-out plug. The knock-out plug on the garbage disposal may not be ‘knocked out’ and therefore in need of maintenance.

Steps for Repairing a Leaking Air Gap

Leaking air gaps are frustrating and unsanitary. Fortunately, there are several steps you can take to repair leaks in your kitchen.

Let’s go through your options:

Remove Visible Clogs

You’ll need to find and remove any visible clogs to resolve an air gap leak.

First, remove the metal casing and plastic top on the air gap fitting. The process will vary depending on your model, but it might unscrew or come off with a pinch and twist.

Afterward, look for any visible clogs. There might be food waste, grease, or other debris. Remove any blockages with a pair of tweezers and see if the issue is resolved.

Remove Larger Blockages

You may have a larger blockage if your air gap still leaks after removing visible clogs. In these cases, you can use different tricks to remove larger debris.

First, place a roll of paper towels over the exposed air gap and blow it into it. You might be able to blow away any blockages.

Otherwise, you can snake out debris with a small tool. You can also vacuum out blockages by placing the hose over the air gap and filling the sink with hot water.

Be sure to run hot water down the air gap after removing blockages to help wipe away any grease or other residue.

Remove the Knock-Out Insert

New garbage disposals require a small insert to be removed during installation. Sometimes, this tiny insert isn’t removed and causes water to leak from the air gap.

Disconnect the hose and power supply to start. Then, you can place a screwdriver against the knock-out insert and tap the end with a hammer until the insert is removed. The dishwasher air gap shouldn’t leak anymore once the insert is removed.

Fix Any Kinks in the Hose

Besides debris, kinks in the air gap tubes or hose can cause leaks. Knots in the hoses are more common with low-quality plastics. Inspect the hoses for any kinks and adjust accordingly to resolve air gap leaks.

How to Prevent a Dishwasher Air Gap From Leaking

Once you recover from an air gap leak, you don’t want to face one again. So, how can you prevent future leaks in your kitchen?

Regular Maintenance

Conduct routine maintenance on your sink, drains, and dishwasher. It might be best to clean out the air gap tubes for food waste or debris every few months.

Alternatively, you can contact a professional plumber for routine services to ensure your kitchen is working correctly.

Check the Lines for Kinks

Another way to prevent leaks is to inspect the hoses for any kinks or knots. Kinks in the line can cause water to back up and leak from the air gap. You may need to adjust the length of the line to prevent leaks.

Use High-Quality Materials

Low-quality plastic tubes are more likely to cause leaks in the air gap. These products are easily damaged and have a greater chance of debris buildup.

Instead, use high-quality rubber hoses to prevent future air gap leaks.

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Hi, I'm Ed, and I run BuildFanatic! I enjoy providing the best possible information on a range of home improvement topics.

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