Lead Architect - Nis

Southern Water; England; On-site; GBP 85,000 - 120,000; Full time

Job summary

Southern Water is seeking an experienced Lead Architect to drive the NIS programme, acting as the architectural authority for OT, IT, data, security and integration. You will define roadmaps, govern design decisions and ensure enterprise standards are met across a large transformation initiative.

You will lead governance, review critical designs, manage dependencies and engage stakeholders to align technology with business outcomes within regulated infrastructure environments.

Qualifications

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

Responsibilities

• 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 with programme leadership to align technology decisions with business outcomes.
• Act as the primary architectural advisor for stakeholders across the programme.

Skills

OT Architecture

Industrial Control Systems

SCADA/PLC/DCS

OPC-UA

Industrial Networking

Cyber Security Standards

Stakeholder Engagement

Governance

Purdue Model

OT-IT integration

Job description

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. 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.