The Waterfall Method: Definition, Pros & Cons and When to Use It

Although numerous managers prefer to use agile methodologies, the waterfall method is still a favorite among organizations with well-defined processes, clear roles, and repetitive projects requiring extensive documentation.

If you’re still looking for the right project management methodology and you’re unsure if the waterfall model can help you achieve the best results possible for your team, you’re in the right place.

This comprehensive guide covers all the essential information you need to know about the waterfall method: what it is, its phases, main advantages and disadvantages, and when you should use it.

What is the waterfall method?

Simply put, the waterfall method is a traditional project management approach, where tasks and phases are completed sequentially with all the work progress flowing in one direction, similar to a waterfall. 

In other words, the next project phase can’t begin if the previous one isn’t finished. Once that happens, there’s no going back.

Moreover, the waterfall methodology demands that all the requirements coming from clients and stakeholders need to be defined from the start to create a thorough project plan.

This plan will include clearly defined roles and milestones and will be followed and documented throughout the project while sticking to those initially set requirements.

Even though the description above might sound strict and unyielding, it helps to remember that this method was first used in the manufacturing and construction industries, where tasks had to be completed in a logical, linear manner on a daily basis.

What are the phases of the waterfall method?

The waterfall method includes the following 5 sequential phases:

1. Gathering the requirements

The goal of this stage is to define and document clear project requirements using client input. By doing this, project managers can efficiently plan the other phases of the project and establish specific goals/deliverables that need to be completed.

2. Designing the framework

Based on the requirements outlined in the previous step, the project manager needs to come up with a feasible concept for the end product that includes concrete specifications.

3. Implementing the solution

At this phase, requirements and features are turned into tasks that will be assigned to and completed by the team. For example, if the project’s end goal is to develop a web application, this is when the coding actually starts.

4. Testing for errors

Once the solution has been developed, a series of tests will be performed to ensure everything works properly. If the final product/services meet the set requirements and all uncovered issues are solved, they are delivered to the client for feedback.

5. Maintenance and updates

During this phase, the client will be regularly using the product/services, discovering and reporting any errors that weren’t spotted in the testing stage. Therefore, the project team will be responsible for fixing those errors and improving the user experience until the client is satisfied.

What are the main advantages and disadvantages of the waterfall method?

Compared to agile, the waterfall approach is great for simplifying project planning, tracking task dependencies, and maintaining structure and balance within a project. Still, it fails in terms of flexibility and adaptability to change.

Advantages of the waterfall method

• Determining the requirements from the beginning helps project managers effortlessly create a project plan, schedule tasks, and give precise budget estimations.
• The phases of the waterfall methodology are straightforward, meaning that they’re easy to follow by all team members without requiring any previous training.
• Uncovering and keeping track of dependencies is simple, as each stage is dependent on the output of the preceding one.
• The lack of overlapping tasks makes it easy to manage tasks, assign resources where needed, and accurately estimate completion time.
• New team members can quickly catch up with the requirements, tasks, and progress thanks to the method’s focus on comprehensive documentation.
• The tasks and stages can be mapped out using a Gantt chart, giving project managers and stakeholders a visual overview of what needs to be done and the current project status.

Disadvantages of the waterfall method

• The fixed, sequential approach lacks flexibility when it comes to unforeseen roadblocks and changes.
• Coming up with specific details might be difficult for clients, and without these, the project manager can’t proceed to the next phase.
• Clients usually have a hard time visualizing the desired outcome from a list of written requirements, which can lead to extensive changes after the project is delivered.
• The client’s limited visibility throughout the project might result in the deliverables not meeting their expectations. 
• Changes can be difficult and costly to implement and the team needs to review the entire project from the beginning, considering that phases are interconnected.
• Having the testing stage almost at the end of the project is extremely risky, especially when the team needs to make large revisions, causing significant delays.

When should you use the waterfall methodology?

As we’ve previously mentioned, the waterfall model is suited for the highly structured work environments found in the constructions and manufacturing industries. But it can also help project managers handle larger teams when agile frameworks such as Scrum and Kanban fall short.

Here are a couple of guidelines you can use to determine if you should use the waterfall method:

IF

• Your project is likely to undergo numerous changes during their life-cycle
• You don’t have a complete list of requirements before the design phase starts
• Your project involves constant testing or requires adjustments based on feedback
• The client wants to be closely involved in the development process

…then the waterfall methodology might not be the best choice for you.

BUT IF

• The scope of your project is clearly defined and will stay the same as the project progresses
• The clients know exactly what they want and it’s easy to gather the requirements you need
• Your project is fairly repetitive and predictable from the beginning until the end
• The standards of the industry you’re working in impose extensive documentation

…you should definitely give it a try!

What about a hybrid approach?

Sometimes the best solution might be to combine two different methodologies, such as waterfall and agile. This allows project managers to take advantage of the strengths of the chosen methods while mitigating their weaknesses.

On the one hand, the systematic approach of the waterfall model is highly efficient for planning and scheduling a project and helping team members get a better understanding of the project scope and the tasks involved. 

On the other hand, the flexibility of the agile method can help with aspects of the implementation phase, including handling changes, incorporating client feedback into the process, and speeding up project delivery.

We’re going to cover the benefits of hybrid project management in a future article, so stay tuned for that. But for now, it’s enough to know that you can create a custom approach and deliver successful projects while using the waterfall method.

Get the most out of your waterfall project with Allegra

Using a powerful project management solution can help you leverage the benefits of the waterfall method and make planning, scheduling, and managing project activities more straightforward.

Allegra is a fully comprehensive project management tool that allows you to visually map tasks and project phases and keep track of dependencies with the help of interactive Gantt charts.

You also get pre-designed reporting templates, such as milestone trend analysis and earned value method, which can help you quickly spot any deviations from the project base plan and take corrective measures if needed. 

To find out more about Allegra’s features and how it can help you deliver projects on time and within budget, check out our complete guide for beginners.