Lead Architect - NIS

Closing Date

2026-12-01

Job Title: Lead Architect - NIS Programme

Location: Falmer or Durrington – Hybrid working (2 days a week)
Hours: 37 hours per week

Salary: depending on skills and experience

We're looking for an experienced Lead Architect to play a pivotal role in one of our most significant operational technology transformation programmes.

As the architectural lead for our NIS programme, you'll be responsible for defining and governing the overall technology architecture, ensuring solutions across Operational Technology (OT), IT, data, security, and integration are aligned, secure, and fit for purpose. You'll act as the key architectural authority, providing technical leadership, driving design decisions, and ensuring compliance with enterprise standards and regulatory requirements.

What will you be doing?

• Lead architecture across a complex, business-critical programme.
• Define and maintain the end-to-end architecture roadmap and key design decisions.
• Ensure alignment across OT, IT, security, data, and technology domains.
• Establish and chair architecture governance and design assurance activities.
• Review and challenge designs from internal teams, system integrators, and third-party vendors.
• Identify and manage architectural risks, dependencies, and cross-programme impacts.
• Work closely with programme leadership and delivery teams to align technology decisions with business outcomes.
• Act as the primary architectural advisor for stakeholders across the programme.

What are we looking for?

We're seeking a highly experienced architect with a strong background in Operational Technology environments and large-scale transformation programmes.

You'll bring:

• Significant experience designing and governing OT and industrial control system environments.
• Strong knowledge of SCADA, PLC, DCS, RTU, HMI and historian technologies.
• Experience of OT networking, segmentation, firewalls and Purdue Model principles.
• Understanding of industrial protocols such as OPC-UA, Modbus/TCP, DNP3, PROFINET and Ethernet/IP.
• Strong knowledge of OT cyber security standards including IEC 62443, NIST, ISO 27001 and NIS requirements.
• Experience integrating OT platforms with enterprise IT, cloud, data and monitoring solutions.
• Proven experience leading architecture across complex programmes or business transformations.
• Excellent stakeholder engagement, governance and decision-making skills.

Desirable

• TOGAF or equivalent architecture certification.
• Security certifications such as CISSP, CISM, GICSP or ISA/IEC 62443.
• Experience working within regulated, critical infrastructure, utilities, energy or transport environments.

Why Join Us?

This is an opportunity to shape the architecture of a major transformation programme that underpins essential services for our customers and communities. You'll work alongside senior stakeholders, influence strategic technology decisions, and help build secure, resilient and future-ready operational technology environments.

At Southern Water, we're committed to creating an inclusive workplace where everyone can thrive, bringing their authentic selves to work and contributing to meaningful change.

Welcome

Our purpose is big. Our impact is huge. And we know that every single one of us has the power, through our actions, to positively change society and the environment for good. It’s why careers with us have real meaning. Because, if you’re driven and ambitious, we can offer you huge opportunities for personal growth, professional development and constant innovation. Forever evolving. Forever focused on doing the right thing, we empower and encourage everyone to play to their strengths and to help us shape a fair and positive future for all. We believe in Water for Life. If you do too, Dive Right In.

We succeed together

Our customers are at the heart of everything we do, because delivering water for life is our core purpose. To achieve this, we need 24/7 support in place to resolve incidents quickly and efficiently. All our employees understand the importance of out-of-hours incident support – because when problems appear, fixing them is our top priority. That’s why our people join together and support when and however needed to make sure our customers get the service they deserve. Joining the Southern Water family means you’ll become part of our incident support team. During your interview, your manager will speak to you about any incident support rotas that apply to your position.

Need flexibility in your work?

Does this opportunity excite you but you’re not 100% sure if you meet all the requirements for the role? Or are you concerned that ‘normal’ office hours aren’t possible given your personal circumstances? Whilst we can’t accommodate every flexible working request, we’ll try to find a practical solution. So why not engage with us and find out more about this role?