Step 2 · Drill Mounting Hole in Countertop
Select a suitable location for the air gap on the countertop, typically near the sink and at least a few inches away from the faucet. The location must be accessible from underneath. Use a tape measure and pencil to mark the center of the hole. Put on safety glasses and a dust mask. Drill a small pilot hole through your mark. Attach the correctly sized hole saw (usually 1-1/4 inch or 1-3/8 inch, check your air gap kit instructions) to your drill. Position the hole saw's pilot bit into your pilot hole and drill slowly and steadily through the countertop. For laminate, applying painter's tape over the drill site can help prevent chipping. Clean up all sawdust and debris from the top and bottom of the new hole.