Commercial plumbing services for Auckland City Hospital project

Size & scope of project

This project involved the construction of a new central plant building (A40) and a tunnel system to provide resilient shared services infrastructure to existing hospital buildings across the Grafton campus. The works included major water storage and distribution assets and new trunk mains extending through the tunnel network to integrate with live hospital facilities.

Services delivered

DLG supplied and installed the complete hydraulic system within the A40 building, including sanitary and stormwater drainage, and fit-out of office and bathroom areas. DLG also installed the hydraulic plant room, including three cold water booster pumps, stainless steel pipework and pumped water main systems serving existing hospital buildings. The scope included a new water storage tank farm capable of storing approximately 1 million litres of potable and non-potable water across four tanks. The systems were designed to support continuity of clinical services and help ensure hospital operations are protected in a natural disaster scenario.

What made this project complex or high-risk?

The project was delivered within an active hospital environment, where safety, access control and operational continuity were critical. The specification was complex and plant-heavy, requiring careful integration of large-scale equipment and strict quality assurance. In addition, thousands of metres of potable and non-potable water mains were installed through the new tunnel system - demanding high levels of coordination, testing discipline, and staged commissioning to avoid disruption to existing services.

Solutions & approach

DLG approached the works with a strong emphasis on risk management, methodical sequencing, and quality control. Working in live hospital zones, our team planned installation and tie-in activities around access requirements and operational constraints, using clear permit-to-work processes, controlled isolations, and detailed communication with site leadership and other trades.

Given the scale of the plant and the critical nature of the network, DLG prioritised buildability and long-term maintainability throughout delivery. Stainless steel pipework and pumped mains were installed with careful attention to support, access clearances and isolation strategy, enabling future servicing without unnecessary shutdowns. The tunnel reticulation was delivered in defined sections to maintain programme certainty and to allow progressive testing, flushing and disinfection as works advanced. Across the tank farm and booster systems, commissioning was treated as a staged process - ensuring performance and redundancy were verified before final integration with live hospital services.

Project results

DLG delivered a high-capacity hydraulic system that strengthened the resilience of Grafton Hospital’s water infrastructure and supported continuity of clinical operations. The new plant, pumped mains and tunnel distribution network provided robust potable and non-potable supply pathways and significant on-site storage - improving the hospital’s ability to maintain essential services during supply disruption or emergency events. By sequencing works carefully in live hospital areas and applying disciplined testing and commissioning, DLG helped minimise operational risk during construction while delivering an infrastructure upgrade designed for long-term reliability, maintainability and disaster readiness.