The Waterfall methodology is a linear, sequential project management approach where progress flows steadily downward through defined phases, such as requirements, design, implementation, and testing. Each stage must be completed and approved before the next begins, making it highly structured but often inflexible to changes. 

Historical Timeline by Era and Year

The history of the Waterfall model spans from early post-WWII engineering to its formalisation in software and eventual institutionalisation in government standards. 

The Pre-Formal Era (1950s – 1969)

During this period, software development borrowed heavily from established engineering and manufacturing processes. 

• 1956: Herbert D. Benington presents a paper on the Semi-Automatic Ground Environment (SAGE) project, describing a structured process that many consider the true technical origin of the sequential approach.
• Late 1960s: Major NASA projects and government software systems for rockets (e.g., Apollo missions) utilise rigid specifications and linear development due to the high cost of changes.
• 1968: The NATO Software Engineering Conference identifies the “software crisis”—projects consistently running over budget and time—leading to a push for more disciplined models. 

The Formalisation Era (1970 – 1979)

The methodology was formally described, ironically as a cautionary tale, and finally given its name. 

• 1970: Dr. Winston W. Royce publishes “Managing the Development of Large Software Systems”. He presents the sequential diagram but explicitly critiques it as “risky and invites failure,” suggesting a more iterative approach instead.
• 1976: The term “Waterfall” is officially coined in a paper by Bell and Thayer, “Software Requirements: Are They a Problem?”. 

The Institutional Era (1980 – 1999)

Waterfall becomes the global standard for large-scale and regulated industries. 

• 1985: The U.S. Department of Defense (DoD) adopts DOD-STD-2167, which mandates the use of the Waterfall model for all software development contractors. This cements Waterfall as the “one true way” for government and aerospace projects.
• 1989: The UK Government creates PRINCE2, a process-based method largely rooted in Waterfall principles, still widely used in the public sector today.
• 1991: In response to Waterfall’s rigidity, James Martin introduces Rapid Application Development (RAD), one of the first major departures from the linear model. 

The Modern & Hybrid Era (2000 – Present)

As Agile became dominant, Waterfall shifted from the default choice to a specialised or hybrid tool. 

• 2001: The Agile Manifesto is published, marking a significant industry-wide shift away from traditional Waterfall toward iterative development.
• 2009: Major institutions like George Washington University and others begin documenting their Project Management Lifecycle (PMLC) to standardise Waterfall and hybrid models for better oversight.
• 2020s: Waterfall persists in regulated domains like healthcare, aerospace, and construction. It is increasingly integrated into hybrid methodologies that use Waterfall for high-level planning and Agile for execution. 

Waterfall Methodology in Project Management, a Timeline History