Waterfall methodology is a sequential process flow. In other words, it means we are planning in advance for an entire project. Much like a waterfall flowing from top to bottom, we start at the top by initiating a process, then planning, then executing, and finally monitoring and controlling the process before it’s completion. Waterfall is commonly used for projects including the mass production of tangible long-term work efforts (a fancy way of saying construction). Chances are, the scope of the project is well known in the beginning, making it easy to pre-plan and execute.
Waterfall has a very formal change control system. We move forward by planning on the scope of work and depending on the requirements collected at the very beginning of planning. This can also help us set an appropriate baseline for project costs.