Waterfall Model in SDLC: Advantages & Disadvantages

By : Lucas Bennett Lucas Bennett
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⚡ Smart Summary

Waterfall Model in SDLC is a sequential development approach that divides a project into fixed phases, each finishing before the next begins. This resource explains its phases, when to use it, and its advantages and disadvantages.

  • 🌊 Waterfall Meaning: The Waterfall Model is a sequential SDLC approach with pre-defined phases and no overlap between them.
  • 📅 Introduced 1970: Winston Royce introduced the model in 1970, and each phase performs one specific activity.
  • 🧱 Six Phases: The phases are requirements, design, build, test, deployment, and maintenance.
  • ✅ When to Use: It suits short, clear projects with stable requirements and technology.
  • ⚖️ Trade-offs: It gives strong documentation and control, but handles changing requirements poorly.
  • 🛡️ Why It Matters: Understanding Waterfall helps teams choose the right model for a project’s needs.
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Waterfall Model in SDLC

What is The Waterfall Model?

Waterfall Model is a sequential model that divides software development into pre-defined phases. Each phase must be completed before the next phase can begin, with no overlap between the phases. Each phase is designed to perform a specific activity during the SDLC. It was introduced in 1970 by Winston Royce.

Explain Waterfall Model in SDLC
Waterfall Model in SDLC

 

Different Phases of Waterfall Model in Software Engineering

Following are the different Waterfall Model phases:

Different phases Activities performed in each stage
Requirement Gathering stage
  • During this phase, the detailed requirements of the software system to be developed are gathered from the client.
Design Stage
  • Plan the programming language, for example Java, PHP, or .NET
  • or a database such as Oracle, MySQL, etc.
  • or other high-level technical details of the project
Built Stage After the design stage comes the build stage, which is nothing but coding the software.
Test Stage In this phase, you test the software to verify that it is built as per the specifications given by the client.
Deployment stage Deploy the application in the respective environment.
Maintenance stage Once your system is ready to use, you may later require changes to the code as per customer requests.

When to use SDLC Waterfall Model?

The Waterfall methodology can be used when:

  • Requirements are not changing frequently
  • The application is not complicated and big
  • The project is short
  • The requirement is clear
  • The environment is stable
  • The technology and tools used are not dynamic and are stable
  • Resources are available and trained

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Advantages and Disadvantages of Waterfall Model

Here are the popular advantages of the Waterfall model in Software Engineering, along with some disadvantages:

Advantages Disadvantages
Before the next phase of development, each phase must be completed. An error can be fixed only during the phase.
Suited for smaller projects where requirements are well defined. It is not desirable for a complex project where requirements change frequently.
A quality assurance test (verification and validation) should be performed before completing each stage. The testing period comes quite late in the development process.
Elaborate documentation is done at every phase of the software’s development cycle. Documentation occupies a lot of the developers’ and testers’ time.
The project is completely dependent on the project team, with minimum client intervention. The client’s valuable feedback cannot be included during the ongoing development phase.
Any changes to the software are made during the development process. Small changes or errors that arise in the completed software may cause a lot of problems.

FAQs

Yes. The Waterfall Model is still used for projects with clear, stable requirements, such as regulated or fixed-scope work. For products where requirements change often, teams usually prefer iterative approaches like Agile instead.

Waterfall is sequential: each phase finishes before the next starts, with little change once underway. Agile is iterative: work is delivered in short cycles with frequent feedback, so requirements can evolve throughout the project.

Not easily. The model is strictly sequential, so returning to an earlier phase is costly and disruptive. This is why clear, well-documented requirements are gathered up front before design and coding begin.

AI assists across the life cycle: drafting requirements, generating and reviewing code, creating test cases, and predicting defects. It speeds up each phase, while engineers still validate the design, code, and results before release.

Yes. AI can analyze documents and stakeholder inputs to draft, organize, and check requirements for gaps or conflicts early. Since Waterfall depends on clear upfront requirements, this reduces costly changes later, though analysts confirm the final scope.

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