Why is Water Spurting Out of My Air Gap?

Have you ever run your dishwasher and then noticed that water is spurting out of your air gap all over the kitchen sink, countertops and even onto the floor? The water may be coming from that weird looking protrusion that positioned next to your faucet, and perhaps you’re wondering what that is? This is known as the air gap, and it’s used to prevent wastewater from backing up into the dishwasher. This can easily occur if the sink has become clogged and the air gap is not working correctly. If there is no air gap, dirty water could be sucked into the dishwasher, and this will make your clean dishes dirty and unsafe to use. Let’s take a closer look at how the air gap works, how it gets clogged and how to fix the problem.

A Dishwasher Installation

When your new dishwasher is installed, the drainage hose will be connected directly to a sink drain, or if you have one, it will be attached to your garbage disposal unit. The hose is known as a dishwasher branch tailpiece wye, and the drain is needed to prevent sewage or drain water from getting back into the dishwasher. This wastewater will contain microbes that could get onto your clean dishes. This will mean that your dishes are coated with bacteria; they will not be safe to use and using them may make you ill.

Every modern dishwasher has a check valve that acts as a safeguard to prevent a backflow of dirty wastewater. But, this may not be sufficient; the amount of debris and loose food that’s expelled during the washing cycle could easily become stuck. Dishwasher manufacturers are aware of this risk of contamination, and this is why there is a drain hose known as an air gap. This offers extra protection against a backflow and experts recommend that all dishwasher users use an air gap.

How Does an Air Gap Work?

When the air gap is working correctly, the dishwasher hose is connected to an input located on the air gap. Water is expelled at the end, gravity works to pull the water down into the hose, and this is carried to the garbage disposal unit. The gap where the water is pulled down is filled with air to prevent the siphoning of dirty water back into your dishwasher. Over time, loose food debris can create a clog in the air gap, and this will prevent the flow of water. Another common issue is that the knockout plug isn’t removed from the water line input when a new garbage disposal is installed. Both of these issues are simple to fix if you have some basic DIY skills and some simple tools.

Removing the Knockout Plug

The most common cause of an air gap clog is a failure to remove the aforementioned knockout plug. The water line that connects to garbage disposal unit is blocked, and the water cannot flow from the dishwasher into to unit and out into the drain. Locate the water line and detach it from the garbage disposal unit, then insert a small screwdriver into the water input and tap it lightly with a hammer. This should cause the knockout plug to pop free, turn off the disposal and reach in with a pair of long nose pliers to remove the knockout plug. Then reattach the water line, restore power to the unit and the dishwasher should be able to drain into the garbage disposal easily.

Fixing a Soft Clog

If you have a softer clog caused by accumulated grease and food debris, you can pop the air gap cap off and place some sort of tube over the hole. A used cardboard tube left over from a paper towel roll works very well. Simply put the tube over the hole and blow into it will as much force as you can muster and the material causing the clog should come loose. Try this a couple of times, but if it doesn’t work, you can try using a wet/dry vacuum or a long bottle brush to clear the clog.

If you’re using a wet/dry vacuum cover the air gap with the hose, turn the unit on and then let it run for around a minute. This should provide ample time for the vacuum to suck out any debris trapped there. If you want to try using a bottle brush, extend the brush down into the air gap and twist it gently until you feel that the resistance has gone. This should remove the debris in the line that leads to the garbage disposal unit.

Check the Attached Hoses

Sometimes, there can be kinks or twists in the hoses that can impede the flow of water. The length of the hose shouldn’t be too long, and there should be as little slack as possible without causing strain on the connectors. The hose should be long enough to reach the highest point underneath the counter if you’re using a “high loop” air gap and it needs to reach the drain or garbage disposal unit. The hoses can be easily removed and trimmed down to size, and this should prevent sagging or kinks from forming in the run to the drain or disposal. This will help to prevent debris from gathering in twists in the hose that could lead to a blockage. It’s also a great idea to use higher quality rubber hoses rather than the cheaper corrugated plastic versions. Debris can easily form in the corrugated sections of the hose, and this can contribute to a blockage.

Some Final Thoughts

Some homeowners believe that the air gap is unnecessary because they have check valves and high loop systems in place. A lot of this reservation is also related to the aesthetic appeal of an air gap in a higher end kitchen. But, although an air gap may not be the prettiest plumbing fixture in your home, it does serve an important function. That being said, there are now air gaps available on the market in a wide variety of finishes and styles, so finding one to suit your kitchen shouldn’t be too hard. If you need more help contact your local certified plumber for expert help and advice.

By Giovanni Longo President Flood Brothers Plumbing
Giovanni Longo is a 3rd generation master plumber who has been practicing his craft and trade in the greater Los Angeles area for well over a decade and a half. A plumbing and hydraulics-engineering innovator, Giovanni’s particular world-class expertise focuses on dealing with challenging sewer system designs as well as resolving complex commercial and residential draining issues. As a certified Flood Mitigation expert, he is also well versed in a wide variety of water damage and remediation solution.