The use of continuous simulations in conjunction with design storms for separate sanitary sewer master planning is a wet-weather analysis approach gaining favor in applications where more rigorous verifications of facility sizes are desired or storage options are viable. However, the benefits of continuous simulations should be weighed against the intensive efforts required to perform these simulations. This paper discusses the issues and results of using continuous simulations for separate sanitary sewer master planning through two case studies, and then summarizes lessons learned for other utilities considering the same decision. KEYWORDSContinuous simulation, design storm, separate sanitary overflows (SSOs), dynamic hydraulic models, sewer master planning, alternative analysis, wet weather