In order to meet the needs of ecological buildings, it is necessary to improve the speed of sewage treatment. Therefore, this study analyzed the impact of zinc oxide nanoparticles on the water supply and drainage of ecological buildings. In the experiment, zinc oxide nanoparticles were selected and the experimental environment was set up to study the treatment effect of nano particles on water supply and drainage wastewater. The experimental results show that: the application of ZnO nanoparticles in water supply and drainage can effectively remove trace elements in sewage and reduce the eutrophication of groundwater; zinc oxide nanoparticles can change the morphology of mold group in sewage and inhibit the growth of sewage. The application of ZnO nanoparticles in the water supply and drainage of ecological buildings can effectively improve the water purification rate and improve the recycling efficiency of water resources.