Waterfall Model & Its Failure

Source: Dev.to

Overview

Waterfall is a linear, phase‑gated software delivery model where work flows downward through fixed stages, and each stage must be completed before the next begins. It was designed for predictability, not speed. Feedback arrives late, and changes are costly.

Phases

Requirements
    ↓
Design
    ↓
Development
    ↓
Testing
    ↓
Deployment
    ↓
Maintenance

Phase Characteristics

• Completed once
• Signed off and locked before moving forward
• No looping back without a formal change request

When Waterfall Works

• Software requirements are stable
• Releases are rare
• Systems are simple
• Hardware is expensive
• Changes are risky

Industries that Used Waterfall Heavily

• Government
• Banking
• Defense
• Telecom

These sectors valued control and documentation more than speed.

Typical Process Details

• Business writes large requirement documents, assuming full clarity upfront.
• Changes are discouraged.
• Architects produce detailed designs; decisions are frozen early, and future assumptions are baked in.
• Development implements based on specifications with minimal user feedback.
• Problems surface late; testing happens near the end.
• Bug fixes are expensive, and time pressure is extreme.
• Manual, risky rollbacks occur after months or years, often with a large blast radius.

Problems

• Bugs and design flaws appear too late.
• Large blast radius makes rollbacks hard.
• Developers rarely see production issues.
• Following the process does not guarantee user satisfaction.

Comparison Table

Common Misconceptions

• Waterfall is “evil.” It is a useful approach when applied to the right context; the issue is misuse.

Why Waterfall Fails

• It assumes certainty in an uncertain world.
• When combined with functional silos, manual operations, and frequent business changes, the model breaks down.

DevOps as a Response

DevOps emerged to address Waterfall’s shortcomings:

• Continuous feedback loops
• Automation of build, test, and deployment pipelines
• Shared ownership across development and operations

By embracing these practices, teams can mitigate the risks inherent in a strictly linear, phase‑gated approach.