A Six-Week Server Refresh That Became a 21-Month Lifecycle Partnership
Greater Western Water engaged Parasyn to upgrade a single Western SCADA site to Windows Server 2022. Four work packages and 21 months later, the engagement is still active — having reshaped the upgrade strategy before it scaled, delivered remote SCADA access, and picked up the next need each time one emerged.
“A six-week server refresh became a 21-month lifecycle partnership: proving a smarter upgrade path before it scaled, then staying on for whatever GWW's SCADA platform needed next.”
Project Overview
Greater Western Water's Western-region SCADA servers were running on ageing Windows infrastructure, spread across a mix of clustered and un-clustered remote sites. Parasyn was engaged (Job Ref: J13515, commenced November 2024) to upgrade the underlying server operating system to Windows Server 2022, starting with a single pilot site.
Rather than closing out once that pilot was done, Parasyn stayed engaged with GWW as the program grew: a proof-of-concept that reshaped the upgrade strategy before wider rollout, a site-by-site rollout across the Western estate, a proof-of-concept for mobile SCADA access, and, most recently, a lab-based security testing work package. Four distinct work packages, delivered under one continuous engagement, with weekly progress reporting sustained throughout.
As of August 2026, the OS upgrade rollout and the Access Anywhere proof of concept are both complete. Parasyn continues to support GWW through the Romsey Test Lab work package, the current focus of an engagement now well past its original scope and timeline.
Technical Scope & Requirements
The scope expanded progressively across four sequential work packages, each emerging from the engagement already underway rather than being tendered separately.
The Challenge — Two Risks That Shaped the Program
Two risks shaped this program: one technical, one logistical.
The efficient-looking path turned out to be the risky one. Bundling the OS upgrade with a SCADA software version upgrade looked like the sensible way to modernise the estate in one pass. Testing proved otherwise: a Head Office server still on the older SCADA version failed to capture data from a site already upgraded to the newer version, and mixed-OS hot/standby failover broke due to an Alarm Server sync issue, serious enough to force a mid-cutover rollback at the pilot site.
The rollout's final site became a many months-long waiting game. Once the OS-only strategy was validated and rolled out, un-clustered followed by the clustered sites moved quickly. The last clustered site, Melton, stalled for months waiting on alternative hardware — a supply-chain delay affecting infrastructure projects industry-wide. Formal completion of the OS upgrade work package slipped well past its original timeline as a result. At another site, meeting a fixed takeover date meant sourcing hardware of a different type rather than waiting for the originally specified units.
The Parasyn Solution — Prove, Then Scale
The version-upgrade risk was caught on one site because Parasyn ran a dedicated proof-of-concept before committing to the wider rollout. The strategy was reset to an OS-only upgrade, decoupled from the SCADA version change, before a single further site went live.
Implementation & Delivery Methodology
- Pilot & Design (Nov 2024 - May 2025)Site discovery, ITMP and Test Procedure development, and initial OS upgrade deployed to the Marriages pilot site.
- Version-Upgrade Strategy POC (Jun - Jul 2025)Bench and on-site testing of mixed SCADA versions and mixed-OS failover. Alarm Server sync issue resolved. OS-only rollout strategy finalised.
- Site-Wide Rollout (Aug 2025 - Jun 2026)Windows Server 2022 upgrade delivered across Western un-clustered and clustered sites, concluding at Melton once alternative hardware arrived.
- Access Anywhere POC (Nov 2025 - Jun 2026)AVEVA Access Anywhere implemented and tested at Rosslynne, running in parallel with the tail of the site rollout.
- Romsey Test Lab (Jul 2026)Lab-based OT/PLC security testing work package, the focus of the engagement.
Project Outcomes & Status
As of August 2026, the OS upgrade rollout and Access Anywhere proof of concept are complete and stable. Parasyn continues to support GWW under the same engagement.
Standards & Frameworks Applied
Lessons Learned & Future Recommendations
| Insight | Impact & Context | Recommendation |
|---|---|---|
| Test the Obvious Path Before Committing to It | Bundling the OS and SCADA version upgrade looked efficient on paper; hands-on testing proved it would have caused data-capture and failover failures across the estate. | Run a dedicated proof-of-concept on one representative site before committing any upgrade strategy to wider rollout. |
| A Continuous Engagement Catches Things a Fixed-Scope Project Will Not | Staying engaged past the original OS-refresh scope let Parasyn pick up Access Anywhere and Romsey Test Lab as they emerged, rather than GWW needing to re-tender each time. | Structure lifecycle engagements with open-ended scope provisions so new needs can be addressed without re-tendering. |
| Have a Substitution Plan, Not Just a Wait List | The final site stalled for months amid industry-wide hardware supply delays, and elsewhere an alternative hardware configuration had to be sourced under a tight deadline. | Identify hardware substitution options at project kick-off, before a delay forces an emergency decision. |
| Plan for the Tail | The Romsey Test Lab work package closed out well past where the program was originally scoped to end. New needs keep surfacing at these sites. | Budget post-rollout lifecycle support as a distinct, open-ended phase on multi-site infrastructure programs. |
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