In the fourth stage, the implementation is frozen and focus is primarily on quality. At the end of the stage, the product is delivered.
One of the goals of the last stage is to make the product sound and of high quality. No known critical errors are allowed in the final product.
The process is then repeated for the next version of the product.
The WaterSluice allows for phase interactions while at the same time putting firm temporal deadlines. The WaterSluice forces all four phases to communicate up front and to work together.
The WaterSluice software engineering methodology assumes the presence of the five level software engineering environment as described in a previous section. Versioning is used to progress the product from one version to another repeating the methodology for each version. Risk management is assumed through out the process. The major components of analysis, the details in the design phase, the four main phases of implementation, and levels of testing proceed as previous described.