How to Install a Dishwasher Air Gap

With a correctly installed air gap, you can have your dishes washed automatically.

Dishwashers make cleaning up after that big meal a snap. These machines work by spraying your dirty dishes with a mixture of soapy water. The dirty water is then pumped out of the dishwasher and into your home's sewage system. Because there is a danger of this dirty water being siphoned back into the clean water supply, some municipalities require a device known as an air gap. These gaps ensure that the water pumped out of the dishwasher stays out of the dishwasher. So before you hook up that brand new high tech dishwasher, check to see if you first have to install a dishwasher air gap.

Things You'll Need

• Air gap
• Drain hoses
• Compression clamps (4)
• Drill (with spade and ceramic drill bits, if needed)
• Screwdriver
• Wrench

Instructions

1. Cut a hole in the countertop above the dishwasher. The size of the hole depends on the dimensions of your air gap. On a laminate countertop, use a spade bit for your drill to make the hole. File down any sharp edges. On a tiled countertop, you will first have to drill out a hole for the air gap with a ceramic drill and then use the spade bit to cut through the wooden countertop underlay.

2. Insert the air gap container into the hole in the countertop until just a few of the threads are showing. Drop the threaded nut over the gap and screw it in until it reaches the countertop.

3. Thread the remaining nut onto the underside of the air gap until the nut is flush with the counter. Give it an additional turn with the wrench.

4. Position the dishwasher so that you can work on the drain line, which is usually located at the back. If the dishwasher is underneath a kitchen counter or other obstacle, pull it out. Make sure you have plenty of space to work. If the dishwasher is already attached to an electric circuit, turn this off.

5. Place one of the compression clamps over the end of the drain hose and tighten just enough to hold it in place. Slip the drain hose over the outlet on the dishwasher. Tighten the compression clamp.

6. Repeat the process from Step 5 with the other end of the drain hose, only this time connect it to the inlet on the air gap. Tighten the compression clamp to secure the drain hose to the air gap.

7. Using the other two compression fittings, connect the outlet on the air gap to your garbage disposal or sink drain, depending on your installation setup.

8. Place the cap on the top of the air gap.

9. Push the dishwater back to its original location. Secure in place with the retention brackets. Run a test cycle. Check the drain line for leaks. Tighten the compression fittings if necessary.

Tips & Warnings

• Check with your local government or utilities agency for the regulations and requirements for air gaps in your location.

• The above steps are just a guideline. Always follow the instructions from your manufacturer.

References

• Danny Lipford: Installing a Dishwasher
• Plumbers Surplus: Installing an Air Gap