Even the best-performing water supply in the country only achieved fluoridation targets 78 percent of the time, research by the University of Otago and the University of Canterbury has found. Photo: 123RF
Gisborne's water is some of the least adequately fluoridated in the country, recent research has uncovered.
The findings, released by the University of Otago and the University of Canterbury, found councils around the country only achieved fluoride targets for drinking water 54 percent of the time over the last 30 years.
Even the best performing water supply only achieved fluoridation targets 78 percent of the time, said Dr Tim Chambers, senior research fellow at the University of Otago in Wellington.
In the case of Gisborne, its fluoride target was achieved only 4 percent of the time.
Chambers said the failures were mostly the result of councils adding too little fluoride to their drinking water.
Only in very rare cases, or 0.2 percent of the time, was too much fluoride added.
"One of the key problems is that a lot of the fluoridation schemes that were installed were done in the 60s, 70s and 80s," Chambers said.
"A lot of it is to do with the maintenance of the fluoridation equipment."
Another issue was that there was no requirement for councils to hit the fluoridation target, and no impact on under-dosing from a regulatory perspective.
Gisborne's water is some of the least adequately fluoridated in the country, research has uncovered. Photo: Liam Clayton / Gisborne Herald
But the impact of councils not hitting the mark could be profound.
Community water fluoridation was one of the key public health interventions available for oral health, Chambers said. It could reduce dental care in children by 40 percent, and dental care in adults by 25 percent.
The researchers analysed fluoride testing data from 25 water suppliers serving more than two million people for the years 1992-2022.
Of the data accumulated, 80 percent was from 2010 onwards due to lost data, which Chambers believed reinforced the need for a national database on drinking water quality.
He hoped Taumata Arowai - the new water services regulator for Aotearoa - would set up a national database of drinking water quality so water suppliers' performance could be monitored.
"At the moment, each council is responsible for keeping their own information. I had to do 67 different official information requests (and) it took about six months and 500 e-mails.
"Taumata Arowai should really have that as a key priority."
Gisborne District Council community lifelines director David Wilson said the council had always focused on ensuring the maximum acceptable value of fluoride was not exceeded in the water supply so as to comply with regulations and ensure safety.
"To avoid too much fluoride being in our water supply, and to achieve regulatory compliance, we have set an operational target which is half the maximum acceptable value," Wilson said.
"However, this is at the lower end of the recommended range for dental health.
Dr Tim Chambers hopes Taumata Arowai - the new water services regulator for Aotearoa - will set up a national database of drinking water quality so water suppliers' performance can be monitored. Photo: Luke Pilkinton-Ching
The council would work to improve its levels to a more suitable level for dental health, he said.
In March, an [independent inquiry was launched into why https://www.rnz.co.nz/news/national/463487/inquiry-announced-into-lack-of-fluoridation-in-wellington-water Wellington Water failed to notify that it had stopped using the fluoride facilities] at two of its treatment plants.
Chambers said the Wellington failure demonstrated even some of New Zealand's largest and most well-resourced councils were struggling to maintain fluoridation schemes.
Dunedin achieved its fluoride target the most consistently out of all councils studied, reaching the mark 78 percent of the time.
The national average was 54 percent.
Local Democracy Reporting is Public Interest Journalism funded through NZ On Air.