The National Cyber Security Centre (NCSC) a part of GCHQ, has added a water sector example to the NCSC’s Secure Connectivity Principles for Operational Technology (OT) demonstrating how organisations can apply the Principles.

The NCSC has published a new fictional worked example which explores how a regional water utility might approach the challenge of standardising digital connectivity across its OT environment while maintaining safety, reliability and cyber resilience.

The example looks at fictional company Admin Corp (used in an earlier data export example) which has now expanded its portfolio to include a regional water utility called Admin Corp Water (ACW). ACW is a regional water utility that treats and distributes potable water to millions of homes and businesses.

The aim of the example is not to prescribe a single architecture or implementation. Instead, it demonstrates how organisations can use the NCSC’s Secure connectivity principles as a target state, while making risk‑informed decisions that reflect their own operational context, regulatory obligations and threat landscape.

The example highlights how architectural choices, governance processes and operational practices all play a role in achieving resilient OT connectivity. In practice, organisations must balance security, safety, reliability and operational requirements, particularly where legacy infrastructure is involved.

Throughout the example, the fictional organisation ‘Admin Corp Water’ works through the eight secure connectivity principles, illustrating how each one can guide design decisions such as reducing exposure, centralising connectivity, managing legacy protocols, strengthening boundaries and preparing for cyber incidents.

This worked example has been developed in collaboration with the Industrial Control Systems Community of Interest (ICS‑COI) Boundary Expert Group. The group brings together practitioners from across critical national infrastructure sectors who are responsible for designing, securing and operating the boundaries between operational technology and external networks. Their insights helped shape both the original guidance and this worked example, ensuring the scenarios and design considerations reflect the realities organisations face when operating critical infrastructure.

The publication also marks an important milestone for the community. It is the first time the Boundary Expert Group has directly authored content for the NCSC website, working collaboratively with the NCSC to validate the technical approaches against the secure connectivity principles. This model allowed practitioner experience and NCSC guidance to be combined to produce a practical and technically grounded worked example.

Click here to access the Secure connectivity principles for operational technology

Click here to access the Secure connectivity - Water Sector Example