Waterfall Methodology

The waterfall methodology is a more traditional software development method in which project requirements are fulfilled in sequential order without any overlapping phases.

When it comes to software development processes, agile, iterative methods seem to dominate the conversation. However, that doesn’t mean that earlier methods, such as the waterfall methodology, are no longer relevant. 

In fact, according to a 2017 survey by the Project Management Institute, more than half of all surveyed project management professionals and executives still use the waterfall methodology either always or frequently. The reality is that every software project is different, and some may be better served by different methods.

In this glossary article, we give an overview of the waterfall methodology, how it differs from agile methods, and how and when to use it for project approaches.

What is the Waterfall Methodology?

The waterfall methodology is an approach to product development that emphasizes a structured, sequential process. It consists of several unique phases with minimal to no overlap with each other, and the product team must complete each phase before moving on to the next. The name “waterfall” comes from the image of each phase cascading down to the next. None of the phases run concurrently.

Waterfall Methodology vs Agile Methodology


Agile Methodology:

The Waterfall methods are characterized by a strict, linear sequence of events. All client requirements are gathered in the beginning, and then the product lead develops a plan of action to execute each of these requirements in order. The Waterfall method provides a fixed, transparent timeline for delivery. However, it is notoriously rigid, so you can’t respond effectively to evolving customer needs.

In contrast, agile frameworks, such as Scrumban are highly iterative. These methods emphasize the rapid and continuous delivery of project components while applying feedback accordingly. Agile methodologies can also revisit earlier stages and change focus and priority very frequently. Agile methods can adapt to changing needs, but improper management can lead to scope creep and prioritization issues.

What Are the Stages of the Waterfall Methodology?

The Waterfall method typically consists of 5 to 7 steps, depending on the variation. However, a common thread remains—each step needs completion first before the next step can begin. Here are the common steps involved: 

1. Gather Customer Requirements

One of the most important parts of the waterfall methodology is that you gather all requirements at the start of the project. They are then documented and locked in. After this phase, the product team will expect no further changes. The project will adhere to a structure and timeline based on the initial requirements.

2. Product Design

In the design phase, the product team designs the product based on the specifications laid out in the initial phase. 

3. Product Development

Once the design is complete, the product team will begin the product development phase. This is where they start transforming designs into working code.

4. Testing

As soon as the product team finishes coding the project, the product is handed over to testers. A QA team as well as the original developers can do the testing. The product team may return to an earlier phase if testing reveals a serious issue with the code or design.

5. Delivery

Once the team has completed all testing, the product is ready for delivery. In this phase, the product team sends all the deliverables to the client, who will then review the completed project and verify that it meets requirements.

6. Maintenance

In the maintenance phase, the client or the target market actively uses the product. There may be issues or bugs that pop up here. During this phase, the product team develops patches, fixes, and updates to resolve them. 

Pros and Cons of the Waterfall Methodology

Despite what some industry professionals may think, the waterfall methodology has certain advantages that make it appropriate for certain types of projects.

  • Documentation: The waterfall method mandates documentation at every phase, including requirements and code. Because of this, it’s easy to turn over product tasks to new developers as needed.
  • Fixed timelines: Unlike agile methods, where requirements can change in between sprints, the waterfall method has all the requirements from the beginning. This means that all the timelines are typically set in stone.
  • Fixed requirements: Product teams and customers align with the requirements from the beginning. This reduces the potential for disagreement and helps manage expectations.
  • Transparency: The fixed timelines and requirements also make it easier to demonstrate progress against the timeline to stakeholders.

Of course, nothing is perfect. There are also some disadvantages that come along with using a waterfall method, making agile methods more desirable in other scenarios:

  • Rigid structure: Because the waterfall methodology is so rigid, it can’t adapt to shifting client and market needs. A client may be unhappy with the final output because their original requirements changed throughout the course of the project.
  • Late feedback: Feedback from the client only occurs towards the end of the waterfall methodology. This can waste a lot of time reworking earlier code and design that didn’t meet new requirements or encountered problems. In a more iterative methodology, feedback takes place much earlier. It can catch mistakes, problems, or new requirements at any time.
  • Poor handling of unclear requirements: The waterfall methodology defines the requirements early on. However, if the client is not yet clear about their requirements at this phase, then the product team may experience issues later on during feedback phases.

When Do You Use the Waterfall Methodology?

Agile frameworks supersede the waterfall methodology in many complex and long-term projects. However, its advantages still make it relevant for certain projects, like those with the following characteristics:

  • clearly defined stable, straightforward requirements
  • Projects with short timelines to meet
  • Simple technology requirements that won’t change during product development
  • Wide availability of expertise and resources on how to create the product components

If all of these elements apply, then a project can leverage the advantages of waterfall methods without needing the continuously iterative advantages of more agile methods.

The Waterfall Methodology: Still Relevant Today

Not all projects are made equal, and not all will need the benefits that agile development confers. The waterfall methodology is still useful for short and simple projects. Knowing how to implement it can give you another perspective for product development that may come in handy more often than you think