A New Zealand-first environmental initiative to harvest grey and rain water is now in use at Bayfair Shopping Centre.

Bayfair's greywater and rainwater harvesting project is expected to reduce the consumption of potable water used by centre's amenities area, currently 1.765 million litres per year, by 56 per cent.

Steve Ellingford with the greywater harvesting system's bladder which holds 22,000 litres of water. Watch the video below.

This is the first time a New Zealand shopping centre has undertaken such a project.

Bayfair Shopping Centre manager Steve Ellingford says the project featured in the centre's environment-focussed development and ambience strategy for several years as a key priority.

In 2012, refurbishment of the centre's main amenities, including public bathrooms and parents' room, were completed.

Pre-plumbing was also undertaken to connect a greywater harvesting system as the first step in the centre's vision to capture and replace potable water.

The Greywater harvesting system will involve diverting wastewater from bathrooms for garden irrigation and, if the greywater is treated, for toilet flushing.

Capturing grey and rainwater will improve the centre's water savings and supplement captured rainwater during dry periods.

Bayfair currently uses about 8589 litres of water per day. Harvesting will capture and replace about 35 per cent of the potable water supply each year and capture and use 24 per cent of the greywater.

On Friday, Aquinas College students officially switched on the system during a celebration with Enviro Challenge ambassadors from the college and Bay of Plenty Regional Council representatives.

Steve says the project is another move to help preserve the region for future generations.

'As a hub of the local community with annual foot traffic in the millions, it goes without saying that we have an impact on our region.

'With water restrictions becoming more common, especially in our region, we want visits to our centre to offer a learning experience and an opportunity for the community to help facilitate more projects.

'This project also demonstrates what can be achieved in an existing building.”

Bay of Plenty Regional Council community engagement advisor Kerry Gosling says the project is a national first and she is excited to have had a hand in it.

'It's great to see a shopping centre in our region at the forefront of sustainable practices, and we hope to see more organisations follow suit.

'It's our hope that Tauranga and the Bay of Plenty region take the national lead in water conservation, and this is a wonderful first step.”

The project is the result of collaboration between several parties, including Tauranga City Council, Bay of Plenty Regional Council, Beca, Tauranga Hardware and Plumbing and Caw Electrical.