What is the Waterfall Model?

The Waterfall Model is a traditional software development methodology that follows a linear and sequential approach. The process flows in one direction — like a waterfall — through clearly defined phases:

Requirements

Design

Implementation (Coding)

Testing

Deployment

Maintenance

Each phase must be completed before the next begins, and there is usually no going back to a previous phase.

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Where is it used?

The Waterfall Model is typically used in:

Projects with well-defined and unchanging requirements

Government or military projects, where documentation and predictability are essential

Short-term projects with low risk

Hardware development, where changes are costly after production starts

Pros of the Waterfall Model:

• Simple and easy to understand
• Clear structure and milestones
• Easy to manage due to rigidity
• Good for smaller projects or those with fixed requirements
• Strong documentation at every stage

Cons of the Waterfall Model:

• Inflexible to changes — hard to go back once a phase is complete
• Late testing — problems may be found late in the process
• Not ideal for complex, evolving projects
• Poor adaptability to customer feedback during development
• High risk and uncertainty if requirements are misunderstood at the start