The article presents some results related to the automation of calculations of wastewater in residential buildings using AutoCAD. Developed using ActiveX technology computer-aided design of the drainage system of a residential building, the following tasks: engineering design of the riser of the sewer network; calculating the throughput of the most loaded riser drainage; calculation of releases of wastewater; hydraulic calculation of yard drainage network; compilation of specifications. The developed program allows you to extend the functionality of AutoCAD.

Keywords: AutoCAD, automation, design of drainage, CAD, ActiveX, AutoCad customization