Stop! Whatever you do, don’t install a pet relief area without proper drainage!Dog Run Drainage Performance is divided into 3 parts:The drainage is affected by the surface area of the sub drainage touching the backer of the turf. If the urine has to find the holes and then find the holes in the drainage underlayment under a stretched and tightened turf that’s a big problem! (AirDrain has 100% vertical drainage all holes open with an inch of air, using gravity to drain)Vertical drainage: How fast can the urine pass all the way into the underlaymentHorizontal Drainage: How fast can the urine be moved to the exit drain? (AirDrain is 92% air)AirDrain is a proven success! With over 600+ K9 areas installed since 2002 for K9 Pet Relief Areas, Pet Playgrounds, Dog Runs, Airport Pet Relief Areas, Kennels, and More...