Security Architect

Southern Water is undergoing a major digital transformation modernising platforms, strengthening resilience and enhancing cyber security across both IT and operational technology (OT) environments. Our customers and communities rely on us every day, and keeping our systems secure is central to protecting essential services.

As our Security Architect, you’ll play a pivotal role within our Digital Architecture function. You’ll work alongside solution architects, security specialists, engineering teams, platform owners and senior stakeholders, shaping secure-by-design principles from the very beginning of the delivery lifecycle. This is a role where your expertise will directly influence the future of our digital estate and strengthen our security posture across the organisation.

What you will be responsible for:

• Defining and assuring security architecture for new and evolving solutions across applications, infrastructure, cloud, data, integration and OT environments.
• Embedding secure-by-design principles into all technology design and delivery processes.
• Translating policy, standards and risk appetite into practical, actionable designs and patterns.
• Identifying and advising on security risks, ensuring appropriate mitigation or formal risk acceptance.
• Providing expert guidance to architecture forums, governance boards and design authorities.
• Supporting solution architects and engineering teams in defining clear security and non-functional requirements.
• Leading or contributing to threat modelling, vulnerability assessments and penetration testing activities.

Additional requirements specific to the role:

• Occasional travel across Southern Water sites and operational locations.
• Participation in governance and design authority forums.
• Engagement with both IT and OT stakeholders, including regulated and safety-critical environments.

• Experience designing and assuring secure solutions across Azure, on-premise and hybrid environments.
• Strong knowledge of industry frameworks such as NCSC guidance, NIST CSF/800-53, ISO 27001/2 or SABSA.
• Understanding of identity & access management, network security, encryption, API security and secrets management.
• Experience with vulnerability management, penetration testing and security assurance processes.
• Ability to define, document and govern security requirements throughout solution delivery.

Desirable:

• Knowledge of NIS Regulations and ISA/IEC 62443 for OT and industrial control systems.
• Experience working in highly regulated industries such as utilities, energy or critical national infrastructure.
• Familiarity with secure operation, monitoring, logging and incident response integration.

Southern Water is at the forefront of transforming Britain’s water industry, investing significantly to enhance resilience, sustainability, and service excellence. With £7.8bn planned investment for 2025-30, this is an unparalleled opportunity to join a business committed to delivering a generational shift in the way water services are managed.

You will be joining at a time of significant change, working alongside a highly skilled leadership team with a clear vision for the future. We offer an environment where senior professionals can make a meaningful impact, influence major strategic decisions, and drive long-term value creation, In line with Southern Water’s security requirements, successful candidates will be required to provide evidence of their identity, eligibility to work in the UK, criminal record