Every time it rains in a New Zealand city, water washing off metal roofs carries dissolved heavy metals directly into stormwater drains, streams, and rivers. Zinc and copper, two of the most widely used roofing materials in the country, are particularly problematic. At elevated concentrations, both metals are toxic to aquatic life, and roof runoff has been identified as one of the primary contributors to heavy metal contamination in urban waterways.
For years, the challenge has been finding a practical solution that builders, developers, and property owners can actually use without significant disruption or cost. A Christchurch-based company has developed one.
How the Storminator System Works
The Storminator is an in-line downpipe treatment system developed from research conducted at the University of Canterbury. It is installed within a building’s existing downpipe and treats stormwater as it flows through, removing heavy metals before they reach the drain.
Independent testing shows the system removes more than 90% of zinc from zinc-based roofs and more than 80% of copper from copper-based roofs. The treatment media inside the unit is made from waste mussel shells sourced in New Zealand, giving the technology a circular economy dimension that has drawn additional interest from environmental agencies and councils.
Practical to Install, Old and New
One of the system’s key advantages is that it can be fitted to new buildings during construction or retrofitted to existing structures without any operational disruption to the building. This makes it viable as both a standard inclusion in new residential and commercial builds and as an upgrade for existing properties in sensitive catchment areas.
For builders and developers working in areas where councils require stormwater quality management as part of consent conditions, the Storminator provides a straightforward path to compliance without complex drainage redesign.
Industry Recognition and Field Trials
The technology has progressed well beyond the laboratory. The venture has received industry awards and completed field trials supported by Environment Canterbury and Christchurch City Council. It now holds patents on the core system and is operating as a commercial product from its Christchurch base.
A Growing Compliance and Design Consideration
As stormwater quality requirements tighten across New Zealand’s urban councils, the question of how new builds manage roof runoff is becoming more prominent in consent and design discussions. For builders and developers looking to get ahead of these requirements, or for those working on projects near sensitive waterways, it is worth understanding what options are now available.
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