Use a tape measure to measure from the back wall of your cabinet to the center of the pipe. Write down this distance for use in Step 2.
Mark your mat
To get the most accurate measurement from the side of the cabinet to the pipe, place your mat in the cabinet right up against the pipe. Mark the mat with a pen to show where the center of pipe is located. Use your measurement from Step 1 to mark the correct distance from the back of the mat in, and draw a circle the size of your pipe. Most drain pipes are either 1 1/4 or 1 1/2 inches in diameter. Most water pipes almost always have a diameter of 1/2 inch.
Cut your mat
Use sharp scissors to cut out the circle you drew. Start by cutting a straight line from the back of the mat to the circle.
Install and seal
Slide your mat into place. In order to keep the mat water tight, we recommend you seal any cuts and around the pipes with clear 100% silicone caulk from the hardware store. It is important that the caulk is 100% silicone like this one.