Waterfall Methodology

The waterfall model is a sequential design process, commonly used in software development processes, in which progress is seen as flowing steadily downwards (just like a waterfall) through the following phases: conception, initiation, analysis, design, construction,  testing, production / implementation and maintenance.

The waterfall development model has its roots in the manufacturing and construction industries: highly structured physical environments in which after-the-fact changes are prohibitively expensive and draws a lot of cost, if not impossible. Since no formal software development methodologies existed at the time, this hardware-oriented model was simply adapted for software development.