Water Treatment Considerations for New Zealand’s Data Centre Sector

New Zealand’s data centre sector continues to grow as demand for cloud services and digital infrastructure increases. Along with power, connectivity, and space, water needs to be considered early in the design (Tech New Zealand, 2025). Data centres may use water for cooling, process systems, site supply, and standby storage. Water may also be recovered for reuse or treated before discharge. Planning these needs early can reduce changes later in the project. 

The Problem: Managing Water Across the Data Centre

The challenge is not only securing a water supply. Each use may need a different water quality, while source-water conditions can vary between locations. Mineral content, hardness, dissolved solids, and silica can differ depending on whether the water comes from a bore, river, or municipal supply. Project teams therefore need to know what is in the water, where it will be used, and the quality required at each point. 

Waldo Andersen, Account Manager at BHF Technologies New Zealand, explains:

“New Zealand has access to established water sources, but availability alone should not drive the design. The critical step is to define the required water quality at each point of use before equipment is selected. This allows the treatment train, storage, controls and recovery strategy to be engineered as one coordinated system, improving reliability, reducing unnecessary demand on treated water and avoiding costly changes later in the project.”

The Approach: Match Treatment to the Use

Once the source water and points of use are clear, the treatment stages can be selected. Ultrafiltration (UF) is used to remove suspended solids, colloids, and microorganisms. Reverse osmosis (RO) is used to reduce dissolved salts and minerals (US Environmental Protection Agency, 2021). UF may be used before RO to protect downstream equipment. RO may then be added where higher-purity water is needed.  

The final treatment train will depend on the source water, system design and required quality. Stored water also needs to remain ready during periods of low use. This requires a system that can maintain water quality without adding unnecessary equipment. 

The Solution: Treatment, Recirculation and Recovery

Recent BHF data centre work has involved recirculating stored water through 25-micron filtration, UV disinfection, and 5-micron filtration on a single skid. In BHF’s recent Australian data centre work, the system is used most of the time during summer, across about four months of the year. Through winter, the water largely sits but still needs to remain available on demand. New Zealand may have a shorter peak-use period because of its cooler climate, although this will depend on the site and cooling system. 

BHF is also exploring standard systems for stored water and a pilot to recover cooling-tower blowdown water for reuse. The aim is to reduce the use of treated drinking water and ease pressure on local supply. A sound water strategy starts with understanding the source, defining each point of use and considering treatment, storage and recovery early. 

Contact Us

BHF welcomes opportunities to work alongside engineering consultants and project teams, sharing practical experience and discussing how these considerations can be applied to future data centre developments.

Talk to our team today, click here.