Thursday, 9 November 2023 Case Studies

Waiau Community Water Supply

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Promax tanks pass the ultimate quake test 

Who: Hurunui District Council

Products: 28x ENDURO 30,000 litre aboveground water tanks

Where: Waiau

Why: The Hurunui District Council had to have complete confidence that the water tanks they installed in the township of Waiau would withstand significant seismic activity. These tanks represented the council’s main water supply to the North Canterbury township, so they had to be robust, durable and flexible. As a tank material, polyethylene ticks all of those boxes. With our reputation for engineering to the highest standards and manufacturing with premium raw materials, the council came to Promax to enquire about our poly tanks.   

What: Promax supplied the council with 28 x 30, 000 litre ENDURO water tanks. With their corrugated design, ENDURO tanks are New Zealand’s strongest water storage tanks; they are so strong they are the only plastic water tanks that can be buried up to one metre in the ground and still retain a 20-year warranty!  

These tanks were installed and in service before the 2016 magnitude 7.8 Waiau Earthquake, the biggest ground-shaking event ever recorded in New Zealand. A seismic measuring instrument at Waiau recorded a vertical acceleration of approximately 3g, or three times the acceleration due to gravity. This is the highest earthquake acceleration force scientifically monitored in New Zealand and as our ENDURO tanks suffered no failures during this event, they have since been referred to in the community as ‘the tanks that withstood the earthquakes’ 


As a footnote: Just up the road in Ward, Promax tanks were brought in to replace the concrete tanks that were damaged during the same earthquake. Yet another reminder that Promax poly tanks are seen as the most robust and dependable tank water source when the earth moves under our feet. 




This case study was originally published in November 2019.