Waterfall Project Management Methodology Explained

If you imagine a waterfall on a river, with the water toppling over the top and not stopping until it hits bottom – and you get the idea about Waterfall project management methodology.

Explained? Well, not quite.  

In short, it is a linear process that flows mostly in one direction from conception to planning to construction to testing to deployment and management of the deliverable in the market.

Unlike other models of project management that work on the idea of iterative phases, there is a minimal reflection and redesign in a Waterfall project.  

Instead, the aim is to keep the momentum of delivery towards completion on a set date to a set deadline.

The Basic Principles

The fundamental principle of waterfall project management is simplicity.  

It is a sequential, linear process made up of discrete phases. These phases are all focused on a stated terminal goal defined at the start. Each phase is reliant on the next. Therefore, if a failure of the project occurs at phase 4, the only option is to go back to phase 1.

As this project management approach was devised and used in sectors such as construction and manufacturing, the strict adherence to the proper execution of each phase is essential.  

In these areas of industry, there are naturally going to be a set order by which things need to be done. If you build a house and pour your concrete foundations before adequately digging out the house footprint, then your only option would be to scrap everything you have done and start all over again.

Therefore, waterfall project management relies on detailed and thorough planning before moving onto the next phase.  

The requirements and deliverables, with the detailed specifications, need to be available from the beginning. All team members need to know their role and the role of others to fulfil their part of the process.

The documentation should be thorough and sent to everyone involved in the project.

How Does It Work?

Waterfall Project Management Methodology Explained

There are six phases in a waterfall project.  These phases will differ based on sector employing the strategy, but the essential theory is the same.

Phase 1 – Requirement Gathering and Documentation

This is the most crucial phase of the project and likely to be where success and failure are set in stone.  This is mostly research and the building of a clear business case. It is also about project design, making sure all people involved in the project know their role.

A good strategy is to create what is sometimes referred to as swimming lanes.  

This is a flow diagram of tasks and outcomes divided amongst team members and laid out along a timeline.  It is also something that can be devised on a GANTT chart, with dependencies set. This way individuals viewing this overview of the work to be done can see how they fit in with the work of others and how any slipping of time can adversely impact on the flow of work.

Phase 2 – System Design

As with most project management strategies, Waterfall has firm roots in software production.

It is where no coding takes place but instead specs are established for how the work should be completed. It is easy to see how this extrapolates out to other sectors.

In construction, for instance, this would be the part of the process where the architect draws out the plans, and the electrician might design the model for lighting, the plumber the model for water and the builder a design of the work cards for different crews.

Phase 3 – Implementation

This is where the product gets produced. Waterfall project management tends to work best where there is a concrete outcome that must be created over a set time.  

Everything in this phase should be already be designed, planned and thoroughly documented in Phase 2. There should be no need to stop to reflect because everything is set in stone in the system design. Individual workflows will be reliant on the whole team doing what is specified.

Phase 4 – Testing

If there are failures at this point, then there is no other choice than to go back to Phase 1 and redesign the whole project.

This is the biggest failure of this methodology and why subsequent project management methodologies tend to emphasise iterative processes, which reflect and adapt the work based on a short burst of work followed by testing.  This way the project stays on track and potential failures are spotted before a point, such as this, where a failure means starting all over again.

However, what you are guaranteed with the waterfall methodology is that there will be no drift from the initial brief and requirements. It is a simple matter of saying we want Z and we are going through steps A – Y to achieve this.

Therefore, the straight line of outcome means the outcome remains fixed. In more iterative processes it is possible for the end deliverable being a long way from the initial customer requirements.

Phase 5 – Delivery

Here the work is complete and submitted to the clients, deployed or released to customers.  

Phase 6 – Maintenance

In the software terms, this phase is about creating the patches and updates that overcomes any problems in the coding.  

In construction, it would be the process of remedying the snag list created by the customer. If there is a significant issue at this stage, it is possible for the project to revert all the way back to phase 1 again and the whole thing starts over.  

Why Should You Use Waterfall Project Management Methodology?

About a quarter of all manufacturing teams use a waterfall methodology.  

This means it is still seen as a successful approach by a lot of companies. There are lots of reasons why it is still used, even though it appears inflexible and potentially costly if errors occur.  

These reasons include:

  1. Simplicity – it is a project management approach that does not need extensive training to implement. It is about thorough documentation from the start and clear delineation of responsibility and accountability. There is no need to worry if a team member is absent or leaves because the plans are in place for another employee to pick up the workflow.
  2. It is easy to see progress – you could almost design a flow diagram that gets coloured in as the project moves towards 100% complete.  There is no fluctuation of progress – it is always moving towards the terminal delivery of the product. This makes it easy to report to clients and senior managers, taking out the guesswork relating to project timelines.
  3. Easy to manage – as the roles and responsibilities are defined from the start, so it is easy for a manager to keep the team accountable for outcomes. It is easy to manage performance because the specification has been laid out and deliverables can be easily tested against expectation and advice were given to improve performance.

Many also believe that ultimately the waterfall project management methodology will save time and therefore money.  

With proper planning at the start, you can ensure deadlines and costs and avoid poor performance. The brief is fixed and agreed from the beginning, so it is highly unlikely that you will disappoint the client or confuse the market. There is no drift of requirements, and therefore people will always pay their bills.

However, there are also those who worry that it does not build in for the unexpected, the exception or the evolving needs of the client. Therefore, it can lead to a loss of time, and high expense as the project returns to phase 1 to begin all over again.  

In fast-paced sectors, such as software design, it is easy to see why most companies have largely dismissed this approach as outdated and inflexible.

In Summary

Waterfall Project Management Methodology vs Agile

Overall, waterfall project management is an excellent approach where the end product is fixed, and there is no variability in time and money.  

Equally, if trial and error, starting the process from the start is in itself a successful model for learning and development, then this linear process works. However, the methodology can be problematic if the end deliverable is unclear and it is difficult to pin down the specifics.

It is not a model that lends itself to flexibility or a process of discovery.  

Testing at such a late stage makes any problem that arises a serious undertaking – which is why most models that have been developed since involves iterative learning processes and constant testing.

Waterfall project management methodology explained simply is a linear process towards a defined outcome.

Its genius is its simplicity. There are no complicated roles to learn or complex structural processes to navigate.

The manager is not worrying where there is a scrum or working out how to update the backlog. It is a model that favours proper, developed planning from the start – with all the uncertainties and potential risks ironed out before the work is undertaken.

Read more about Project Management Methodologies.

About Alex 46 Articles
The idea behind ThinkThyme was born when Alex realised a huge niche on the market - the lack of an educational and informational platform for young Project Managers and Product Owners. With over 7 years of experience in Product Management, Alex shares everything she had to learn herself on-the-go.

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