Plumbing and piping plans show the location of fixtures, pipes, and valves. You can lay out plumbing plans on a blank page or as a layer in an existing floor plan. To accept the size and scale of the CAD drawing, click OK. Note: If the drawing scale of the CAD drawing is different from the scale of Plumbing CAD Drawings Free Architectural Plumbing CAD drawings and blocks for download in dwg or pdf formats for use with AutoCAD and other 2D and 3D design software. By downloading and using any ARCAT CAD detail content you agree to the following [ license agreement ].