What is Waterfall Model? How to Use it? [Various Phases Explained]

Project management processes need a set of rules, methodologies, and tools to manage a project effectively. One of the best methodologies for project management is the waterfall model, which fuels a project management process to reach its completion without any roadblocks.

Coined under the guidance of Winston W. Royce in 1970, the waterfall approach sets standards for defining work structure for the effective management of projects through a logical flow of work. 

Let’s dive deep into the realm of the waterfall approach to understand its workings and the reasons behind its success!

Understanding Waterfall Model

The waterfall model is a linear, sequential methodology to the SDLC (software development lifecycle), extensively used in software engineering and product development. Alternatively referred to as a classic life cycle model or a linear sequential life cycle model, the methodology gets its name from the fact that a project’s SDLC steps logically progress similarly to the flow of water across a cliff’s edge.

The model defines discrete goals for every phase of development. These goals or endpoints can’t be reexamined after their completion. Specifically, the next stage commences after each previous step is completed.

In other words, the waterfall model is a clear-cut linear project management system. It involves sequential execution of tasks, beginning from the top with feasibility and progressing down through different tasks with execution into the live environment. The project implementation occurs based on proposed requirements and designs. Finally, the end product is tested and verified before the launch.

A massive project is collapsed into various scheduled phases with related tasks. So it ensures easy and timely completion of the project. Since it is an efficient and organised model, all the team members will hone their skills.

Why use the Waterfall Model?

After understanding what is waterfall model, it is equally significant to know the reasons for using it. Let’s explore the various benefits of implementing the waterfall model. 

  • It is a reliable, efficient methodology that guarantees project managers efficient workflows and enhanced team productivity.
  • It ensures all deliverables are fulfilled with adequate attention to detail.
  • It keeps an eye on reducing the occurrences of errors. Hence, it makes sure your projects’ outcomes stay unaffected by errors.
  • It is perfect for small and low-budget projects with well-defined requirements.
  • The process and outcomes are well documented.
  • All the phases of the waterfall model are predictable, reliable, and straightforward. Hence, any team member can effortlessly understand the entire development process.
  • The well-defined stages without overlap simplify the handling operations.
  • Its rigidity makes it suitable for enormous, long-term projects that depend on multiple moving components.
  • It is worthwhile for tracking tasks with dependencies. The process of finding and solving dependencies is easy because the next phase begins after each of the previous phases is completed.

How to Use the Waterfall Model?

The phases discussed below will eliminate your confusion about how to use the waterfall model.


Only comprehending what is waterfall model and why you should use it will not suffice. Knowing the phases or stages discussed below will help you effectively use the model.

Here are the 7 phases of the waterfall model.

1) Requirement Collection and Documentation

2) Project Analysis

3) System Design

4) Implementation

5) Integration and Testing

6) System Deployment

7) Maintenance

Let’s understand each of these phases.

1) Requirement Collection and Documentation

This phase of the waterfall methodology collects and documents all the essential requirements for a system’s development. The project manager depends on project requirements to outline specifications and plans. These requirements and collected before the project commences while ensuring that no changes are allowed while the project continues.

The phase’s outcome denotes a project requirements document that implies that the essential data is collected and no further customer intervention is needed.

This phase involves the following steps:

  • Determining objectives linked with developing your app/project.
  • To match the project scope with the stakeholders’ expectations, you must conduct interviews to determine the client’s expectations.
  • Research the existing market, clients’ needs, and competing apps. This stage helps you discover the niches your app/project can serve.
  • Bring all relevant workforces (designers to programmers) and resources together to develop the app/project.
  • Organise a meeting with stakeholders and your team to discuss the gathered information and defined expectations.

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2) Project Analysis

This phase involves reviewing the project specifications from a business viewpoint. It audits financial and technical resources for feasibility. The evaluated requirements are specified in an SRS (software requirement specification) document. This document resolves potential future disputes between the SRS development teams and the customer.

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3) System Design

It involves developing the system’s general framework, explicit functions, and architecture. In order to design the entire system, you must determine the software requirements and system architecture. To accomplish this, you will need the information you collected during the first phase.

The following points help you to design your proposed system effectively.

  • List all the tasks that are crucial to achieving the ultimate deliverable.
  • Estimate the time required to complete each task. Map the tasks on the Gantt chart and carefully link dependencies.

4) Implementation

This phase develops, tests, and prepares all components of the system. It is the core phase of the waterfall model as it builds and tests the project/app. Firstly, the system is developed into smaller units. Subsequently, each unit passes through a unit testing process before being assimilated.

It involves the following steps:

  • Assign tasks to the team
  • Monitor and track the implementation process
  • Manage resources and workload
  • Inform stakeholders about the progress of the project implementation

5) Integration and Testing:

This phase involves the following steps.

  • Integrate the individual units developed in the above phase into a singular system. 
  • Conduct an integration testing process to authenticate that the components of your project/app work collectively and efficiently.
  • Test the whole system to make sure all units function.

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6) System Deployment

Before starting this phase of the waterfall methodology, make sure you verify that your project/app is working. Subsequently, the developed system is deployed and used for its targeted purpose. Although the app is delivered, the SDLC is not yet finished until you accomplish specific administrative tasks. These tasks are listed below.

  • Determine pay contracts: Live up to your contractual obligations to your team and other freelance contractors.
  • Create a template: Prepare a project template that helps you easily develop other projects.
  • Finalise paperwork: Ascertain that all paperwork has been notarised and documented.
  • Encourage: Encourage all the involved team members to keep up their performances for upcoming projects.

7) Maintenance

Your project is incomplete without authentication and verification. This phase addresses ongoing issues by releasing patches, updates, or advanced system versions. It is an ongoing post-launch phase that lasts as long as your contract continues.

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The waterfall model is a straightforward SDLC approach that guarantees smooth and timely project completion. It is best suitable for small software development projects since the design, development, and execution are easier in smaller projects compared to larger ones. Make sure to use reliable software that provides sufficient resources to fulfil the quality standards, deadlines, and other clients’ requirements.

Q. When must you use a waterfall method?

You must use a waterfall method in the following cases. (i) Requirements are clearly defined and may not modify. (ii) When the proposed technology is perfectly understood. (iii) The project is short-term. (iv). Risk is minimum or zero.

Q. What are the disadvantages of using a waterfall method?

Here are the disadvantages of using a waterfall method: (i) It is not suitable for object-oriented and complex projects and projects whose requirements are vulnerable to the risk of modification. (ii) There is no feedback path and no overlying phases. (iii) It is difficult to evaluate progress within stages. (iv) It is difficult to assimilate change requests. (v) Amending scope during the life cycle can terminate a project.

Q. What is the modified waterfall model?

The modified waterfall model offers a systematic sequence of developmental steps. The involved phases are identical to that of the classic waterfall model. However, the phases are allowed to overlap and disintegrate the project into subprojects. The flexible, iterative phases will facilitate the acceptability and relevance of documentation. They guarantee the reliability, quality, and easy maintenance of the designed custom system.

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