As a result, significant pressure fluctuations around the initial steady state can be observed. These changes can be caused by pump stop, pump start (pipe filling), rapid inline valve closure, pipe burst, rapid demand change, and other factors. Hydraulic transient phenomena in closed pipeline systems occur when flow experiences sudden changes. The tool identified sensitive parameters of the case study model and achieved much better accuracy than the initial model setup after calibration. The tool was tested and applied in a transient study of a sewer system pumping station upgrade. The tool also enables calibration for field testing pressures. The tool supports sensitivity analysis for the Hazen–Williams c coefficient for a steady state model, and for the inertia of pump plus motor and pipe wave speed for a transient model. The tool was created by coupling Bentley WaterObjects.NET, programming language C#, and genetic library in AForge.NET. An in-house tool was developed to enable efficient sensitivity analysis and calibration study for Bentley’s HAMMER steady state and transient models.