How to Install an Air Trap for a Bar Sink

Measure the bottom of the air gap with the measuring tape. Choose a drill bit 1/8 inch larger than the bottom of the air gap and place it in the drill.

Drill a hole through either the rim of the sink beside the faucet assembly or through the countertop itself. Place the air gap in the hole. The two nipples on the bottom will hang down into the sink cabinet, leaving about an inch of the air gap sticking up above the countertop.

Open the sink's cabinet doors. Slide a hose clamp over the end of the dishwasher's drain hose, then connect the drain hose end to the larger of the two nipples on the bottom of the air gap. Tighten the hose clamp to secure the dishwasher hose in place.

Place hose clamps on each end of another length of drain hose. Attach one end to the free nipple on the air gap and the other to the garbage disposal's tailpiece. If the hose is too long, cut it down with the utility knife so it better fits within the sink cabinet.

Place the cap from the air gap kit on the portion of the air gap protruding from the top of the sink or countertop. The cap is usually available in a chrome or nickel finish, so you can choose one that matches your faucet.