Ministry of Education head Peter Hughes has made a plea to all schools, asking them to consider ditching sugary drinks in favour of water to help tackle childhood obesity.
Yendarra School in Otara went water-only 10 years ago, and principal Susan Dunlop told Newstalk ZB there was no downside.
She said the children are easier to teach and their dental health is better than many other nearby schools.
She said one parent complained when the school initially went water-only, but now everyone understood the benefits.
The Heart Foundation has applauded the Ministry of Education for the call.