The Waterfall Model, also known as the classic life cycle, is a traditional approach to software development that begins with the definition of customer requirements and continues through planning, modeling, construction, and implementation to ongoing product support. This model provides a general overview and suggests a sequence of events for the developer to handle. Also, it is used to describe software development activities in different contexts.
In this blog, we discussed some of the essential topics that you must know about the Waterfall Model.
Table of Contents:
What is the Waterfall Model?
The Waterfall Model is the earliest SDLC method that was used for software development. In the Waterfall Model, the entire software development process is divided into separate phases. The result of one step serves as input for the next step in the sequence. This means that each stage of the development process starts only after the previous stage is completed.
One of the key requirements of this model is that the user clearly defines the complete requirements early in development. It is very useful for developers to agree on what to do now. Its simplicity makes it easy to explain to users who are not familiar with the software development process.
Phases of the Waterfall Model
The Waterfall Model follows a hierarchical process, completing each phase with detailed confirmation before moving on to the next. It is a method where each phase must be finished before the next can begin. You must understand every stage of the Waterfall Model in order to gain a more thorough understanding of it.
Below is the diagrammatic representation of the different phases of the Waterfall Model. So let’s get started!
1. Requirement Analysis
In this Requirement Analysis, all the detailed requirements are collected from the customer who wants to develop the software. After obtaining the requirements, the system analyst analyzes whether the requirements can be fulfilled. The software development team then moves into the design phase. A Software Requirements Specification (SRS) is maintained to reflect the requirements. It also gives you the ability to define your product’s hardware or software requirements at every stage of design, development, and modification.
2. System Design
After the first step is completed and verified, the second step becomes important. This step helps determine the software and hardware requirements for product development. It also helps solve Software Requirements Specification (SRS) documentation in the design and development of software products functional. This work involves the analysts and designers which results in the analysis and design documentation of the systems. The design document is used as a template for further coding.
3. Implementation
Encryption is done at this stage. The programmer extracts the information from the previous step and creates an operational product. Code is usually implemented in small parts that are integrated at the end of this phase or at the beginning of the next phase. The result of the development phase is a software product that is tested as a finished product in the next phase. With the help of system design, the system is further developed into smaller programs, which are called integrated units in the next step.
4. Testing
This step verifies that the individual components and the integrated parts are error-free and fully act in accordance with the requirements defined in the first step. An independent quality assurance team defines test cases to determine whether the product partially or fully meets the requirements defined in the first step. During this testing phase, various quality and customer satisfaction metrics are used to measure project success.
5. Deployment
The deployment is the final stage of the entire software development life cycle (SDLC) that brings the application into production. Once the software team has developed the application and completed all the testing steps, the software is ready for distribution. This means that the software is ready for all real-world users.
6. Maintenance
The SDLC doesn’t end when the software is in the market. During the maintenance phase, the main task is to ensure that the software is available and working correctly and also to fix any user-reported bugs that may have been misplaced during the testing phase. Developers move to the maintenance phase and take the necessary steps to resolve issues that are reported by end users.
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Features of the SDLC Waterfall Model
1. Linear and Sequential Process
The Waterfall Model follows a chronological order, where each phase is completed before moving to the next phase.
2. Clear Documentation
Each phase produces well-documented outputs, ensuring clarity for developers and stakeholders.
3. Well-Defined Phases
The model consists of many phases: Requirement Analysis, System Design, Implementation, Testing, Deployment, and Maintenance.
4. No Overlapping Phases
Each phase has a different start, different role and end point, which is preventing overlapping or iterative development.
5. Best for Well-Defined Projects
Works well for projects where the requirements are clear, and fixed and where changes are unlikely to happen.
Example of Waterfall Model
Let’s see what steps would be taken, to develop a banking application while working with the waterfall model. Here the first step is Requirement Analysis,
1. Requirement Analysis
At this stage, the bank collaborates with business analysts and stakeholders to define the complete set of requirements, such as:
- User authentication and authorization
- Account creation and management
- Fund transfer functionality
- Loan and credit card services
- Transaction history and statements
- Security and compliance with banking regulations
2. System Design
Once the requirements are finalized, system architects and UI/UX designers create a blueprint of the system:
- High-Level Design (HLD): This is used to define the overall architecture, databases, and security models.
- Low-Level Design (LLD): This breaks down each module, specifying the technologies, data flow, and API interactions.
- User Interface (UI) Design: Wireframes for mobile and web interfaces are prepared.
3. Implementation
Developers start writing code based on the design specifications. The project is divided into different modules:
- User Authentication Module – For secure login, OTP verification, and encryption.
- Account Management Module – Handles the creation of accounts, balance checks, and account types (savings, current, etc.).
- Transaction Module – Develops features for fund transfers, payments, and auto-debits.
- Security Module – Integrates encryption, fraud detection, and compliance checks.
4. Testing
After implementation, the Quality Assurance (QA) team conducts various levels of testing:
- Unit Testing: Individual functions and modules are tested for correctness.
- Integration Testing: Different modules are connected and tested as a whole.
- System Testing: The entire banking system is tested in a controlled environment.
- Security Testing: Ensures compliance with banking standards (e.g., PCI-DSS) and prevents fraud.
- Performance Testing: Checks if the system can handle thousands of simultaneous transactions.
5. Deployment
Once the system is tested and it is approved, the banking application is deployed in a live environment. This phase is as follows:
- Deploying the application on banking servers
- Ensuring proper database configurations
- Enabling security protocols such as HTTPS, firewalls, and monitoring tools
- Training bank employees to use the software
6. Maintenance and Updates
After deployment is done, the software goes to the maintenance phase, which involves:
- System Upgrades: Keeping up with new banking regulations and compliance requirements.
- Bug Fixes: Addressing any unexpected issues reported by users.
- Security Patches: Updating security measures to prevent cyber threats.
- Feature Enhancements: Adding new functionalities like mobile payments, AI-based fraud detection, etc.
Applications of the Waterfall Model
The Waterfall Model is widely used in software development and also in other industries where a structured and sequential approach is required. Below are some key areas where the Waterfall Model is commonly used:
1. Banking and Financial Software Development
- It is used in applications that require high security, accuracy, and compliance with regulatory standards
- It is used in banking transaction systems, financial reporting software, and payment gateways.
2. Healthcare and Medical Software
- It is Critical for ensuring accuracy and compliance with healthcare regulations such as HIPAA.
- It is used in patient record management systems, hospital management software, and diagnostic tools.
3. Government and Defence Projects
- It is Ideal for large-scale projects where requirements are well-defined and need strict documentation.
- It is used in military software, aerospace systems, and national security applications.
4. Embedded Systems and Firmware Development
- It is suitable for systems with hardware dependencies, where changes in requirements are minimal.
- Used in microcontrollers, automotive software, and industrial automation.
5. Enterprise Resource Planning (ERP) Systems
- Large, complex projects that require detailed planning and documentation benefit from the Waterfall approach.
- Used in ERP solutions for businesses, supply chain management, and inventory control systems.
6. Construction and Engineering Projects
- The sequential flow of the Waterfall Model aligns with the physical project development stages.
- Used in architectural planning, civil engineering, and infrastructure projects.
7. Educational and Learning Management Systems (LMS)
- This is used in developing e-learning platforms and online examination systems, where requirements are predefined.
8. Telecommunication and Networking Software
- This is used for software in network infrastructure, mobile communication systems, and internet service providers.
Advantages of the Waterfall Model
The advantage of the Waterfall Model is that it allows distribution and departmental control. You can set a timeline for each development phase and step into the product development process model.
Some of the main advantages of the Waterfall Model in Software Engineering are:
- A Waterfall Model is simple, easy to understand, and easy to use.
- A Waterfall Model cannot move to the next step until the previous step is complete, so data is always correctly written from one step to the next. It ensures a smooth and orderly transfer of information between stages.
- The output after the completion of each step ensures high visibility of the Waterfall Model. By analyzing the results of each phase, the project manager and the client can conclude that the project was a deep success.
- The steps are executed and completed one by one.
- The Waterfall Model is suitable for small projects with well-defined and well-understood requirements.
Disadvantages of Waterfall Model
Waterfall Model is one of the reputable models, but recently it has faced objections for being an out-of-date model. The model’s regulations become more prominent relying on the size, type, and goals of the project. Instead of adjusting your organization to Waterfall’s guidelines later, consider these regulations to think about whether Waterfall is really a fit for your software development process.
So, here are some of the disadvantages of the Waterfall Model in Software Engineering:
- All the stages are interconnected, so even a small change in the previous stage can lead to big problems in the next stage.
- It is difficult to measure progress within stages.
- The Waterfall Model does not adapt to changing customer needs.
- There are many risks and uncertainties.
- As testing is done at a later stage, problems and risks may not be identified early, making it difficult to develop a risk management strategy.
- At the end of the life cycle, the working model is visible, i.e after the implementation phase.
- While one team member is working on one platform, other team members have to wait until the next step is completed.
Waterfall Model vs. Agile
| Aspects |
Waterfall |
Agile |
| Approach |
Sequential & structured |
Iterative & flexible |
| Development Process |
Divided into a number of phases |
It is a continuous cycle |
| Requirement Changes |
Difficult to make the changes |
Easily adapts the changing requirements |
| Risk Management |
Risks are identified late in the process |
Risks are identified early |
| Testing |
Done after the development phase |
Testing is done continuously, in every cycle |
| Use Case |
Best for Large Scale Projects with fixed requirements |
Best for Evolving projects |
Conclusion
The Waterfall Model works best if you can clearly define two requirements, i.e system and software requirements. All requirements must be documented to simplify requirements-based software development. A Waterfall Model can be considered the best example if you have a good understanding of the final product. This model is suitable when the project is relatively simple and the requirements do not change regularly. It became very popular because it clearly explains each step with logical and progressive information. This helps developers quickly identify requirements during the development process.