Install Drain Clean-Out, Install Clean-Out Drain, Clean-Outs, Clean-Out Drains A clean-out is usually installed when the plumbing pipe is run for a kitchen sink. Most of these are found outside the house located below the kitchen window. This clean-out allows for easy access when there’s a need to snake the kitchen drain line. In the picture shown here, a 2” cast iron clean-out was installed and over the years a PVC plug has replaced the old brass plug which was used years ago.