Waterfall Project Management: 6 Phases & When to Use It
Waterfall project management is a linear methodology that involves completing planning and meetings upfront to determine project scope, requirements, and risks.
It's the right method for your project if your requirements are specific and fixed, previous stages need to be completed before future ones can begin, and changes or revisions after the project has started are limited. Here's how waterfall project management works.
What Is Waterfall Project Management?
Waterfall project management is a linear project management methodology that moves through distinct phases of work. The next phase of work is dependent on the previous phase, so only one project phase can be worked on at a time.
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The project plan in a waterfall project is mapped out in great detail, with milestones along the way from project initiation to project closure.
Agile vs Waterfall Project Management
The main difference between agile and waterfall is that agile focuses on iteration and adaptability and you can change your plan to accommodate new requirements and feedback along the way, but waterfall project management follows a linear plan from project start to finish.
| Aspect | Waterfall | Agile |
|---|---|---|
| Project planning | Detailed planning occurs upfront. | Planning evolves throughout the project. |
| Workflow | Work follows sequential phases. | Work progresses through iterative cycles. |
| Requirements | Best suited to clearly defined, stable requirements. | Accommodates changing requirements. |
| Flexibility | Changes often require formal revisions and rework. | Changes can be incorporated between iterations. |
| Delivery | The completed product is typically delivered near the end. | Usable increments can be delivered more frequently. |
| Stakeholder feedback | Primarily gathered at planned reviews and milestones. | Gathered regularly throughout development. |
Additionally, some teams may even combine both methodologies, practicing what's called "water-agile-fall."
In Scrum, an agile framework, work is organized in a backlog and completed in time-boxed sprints. Each sprint aims to produce a usable product increment, allowing stakeholders to review progress and provide feedback.
The 6 Phases of Waterfall Project Management
When you use waterfall, your project goes through six sequential phases. You'll use the project life cycle in conjunction—the steps below overlap with the five phases of project initiation, planning, execution, monitoring and controlling, and closure.
| Phase | Main Activity | Typical Deliverable |
|---|---|---|
| 1. Requirements Gathering | Define project scope, requirements, and expectations. | Requirements document |
| 2. Design | Develop solutions based on approved requirements. | Approved designs or specifications |
| 3. Implementation | Build the product or execute the project plan. | Working product or completed project components |
| 4. Testing & QA | Verify deliverables and resolve defects. | Tested and validated deliverables |
| 5. Deployment | Release the completed product. | Live product and maintenance plan |
| 6. Maintenance | Address issues and maintain functionality. | Fixes, updates, and maintenance records |
1. Requirements Gathering
In the first step of the waterfall methodology, you'll gather all of the project requirements. This involves talking to your stakeholders and your team, reviewing the project charter and any other scope documents, and outlining specific deliverables and activities.
You'll gather four types of requirements:
- Functional requirements
- Technical requirements
- Non-functional requirements
- System requirements
Document these in your requirements document alongside your project plan. Update the documentation if requirements change during the project.
Review this document with your project team before kicking off the work, and make sure to get buy-in from any external stakeholders or clients as well (this is often done during the project kickoff).
2. Design
In this step, your project team will begin designing solutions based on the requirements. Assign deliverables to team members based on their availability and skillset (using project management software).
The exact deliverables will depend on the type of project you're working on (e.g. for a website project, the team should deliver wireframes and webpage designs).
As the project manager, your responsibilities during this phase include:
- Reviewing deliverables: Review designs and provide feedback to the team.
- Managing timelines: Track deliverables and due dates.
- Monitoring the critical path: Identify tasks that could delay the project and make sure the project stays on track.
Once designs are approved by stakeholders or clients, you can move on.
3. Implementation
In the implementation phase, the development team implements the designs created in the previous stage. Once again, as the project manager, you'll be keeping an eye on the timeline and assigning tasks.
You'll also need to monitor the project for potential risks and dependencies that could arise and to make sure budget isn't being used up too quickly.
The deliverables for the development process will again depend on your project type. For our website project example, deliverables will include working web pages (likely in a staging or non-live environment first to allow for quality assurance).
In this phase, you might discover that something created in the design phase isn't technically possible, which might require you to go back to the previous stage and rework the designs (which will cost you time). You can mitigate this by having the software development team involved in reviewing designs.
4. Testing & Quality Assurance
In this phase, you and your team will test and review the quality of what's been delivered to make sure it meets requirements and stakeholder expectations.
The project team takes care of this, but if you as the project manager have a technical background, you might be involved as well.
During testing and quality assurance, the team should:
- Create test cases to verify that deliverables meet requirements.
- Document bugs and issues that need to be resolved.
- Evaluate quality against the metrics established during requirements gathering.
- Review use cases to confirm that expected functionality has been covered.
You might need to send the project back to your developers to fix any major bugs or issues that you discover in this process. This is why it's important to build extra time into your project for the testing phase—you don't want to get held up fixing bugs at the last minute.
5. Deployment
Once the team has fixed all bugs and issues that were found during the quality assurance workflow, the team can deploy the project. The deliverable here is the live product, along with a plan to maintain it (see information on the maintenance phase below) and documentation around what's been delivered.
Monitor the live product for any bugs or issues that were missed in the quality assurance phase, and as the project manager, you'll need to be in constant communication with stakeholders or clients to make sure everything is unfolding according to expectations.
6. Maintenance
Next, the team will perform maintenance on the product according to the plan laid out in the previous step. Be clear with stakeholders or clients about what is included in the plan as regular maintenance and what is out of scope and may incur an extra cost (e.g. new features, additional pages, etc.).
3 Use Cases For Waterfall Project Management
Waterfall project management works best for projects that have well-defined deliverables and constraints as well as fixed budgets and timelines.
If your project scope still has a lot of unknowns or is subject to change, waterfall is probably not the project management approach you want to use. Waterfall works best for the following types of projects:
Construction Projects
Construction (also known as capital project management) lends itself well to the waterfall method because a strict project management process helps ensure the safety of everyone working on the project or using the finished product.
This is because plans for buildings need to be signed off on by engineers and often government agencies before they can begin. Plans are not subject to change along the way, and a sequential plan can easily be followed.
There are specialized construction project management software tools you can use for this type of project, as well as AI tools for construction project management.
Website Design and Build Projects
Website design and build projects might use the waterfall process or one of many agile methods. Waterfall works well when needs are well-defined.
If you have an exact sitemap and style guide you need to use, it’s easy to plan out the phases and when each page will be ready for review and approval. You can also select your target launch date with a high level of confidence.
Software with Specific Functionality
If your team is building software with specific functionality and a well-defined set of requirements, the waterfall model might be the right choice. Examples of this might be a CRM system, HR software, or any type of compliance tool.
These will have an initial set of requirements, and the work can be scheduled and completed in a linear fashion. A Gantt chart showing the timeline and when stakeholders will receive status updates and/or need to be available for user acceptance testing will get everyone aligned with your plan.
Pros and Cons of Waterfall Project Management
Waterfall project management offers clear structure, defined responsibilities, and thorough documentation, but its sequential approach can make changes more difficult. Understanding the pros and cons can help you determine whether this methodology is the right fit for your project.
| Pros | Cons |
| Upfront planning: Planning happens before work begins, reducing ambiguity and unexpected changes. | Rigid structure: Changes are difficult to accommodate once the project is underway. |
| Clear responsibilities: Team members understand their roles and timelines. | Limited flexibility: Evolving technology or user requirements can be difficult to incorporate. |
| Defined objectives: Teams and stakeholders share a clear project plan and objectives. | Longer planning process: Extensive upfront planning can delay the start of implementation. |
| Scope control: New ideas can be deferred to future work or handled through change orders. | Delayed delivery: Sequential phases can delay delivery of a usable product compared with agile approaches. |
| Easier handoffs: Documented requirements and design decisions help teams transition between project phases. | Late problem discovery: Issues may not be identified until the testing phase. |
| Better documentation: Recorded decisions and approvals provide references for new team members. | Costly rework: Problems discovered late may require revisiting completed phases, increasing costs and delaying delivery. |
What's Next?
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