Palmer said there were obvious health risks with over-dosing the supply.
“Our priority as the regulator at the time was to ensure that over-dosing did not occur.”
Health New Zealand was working closely with the Ministry of Health, Taumata Arowai (the new regulator), and Wellington Water to ensure a solution was found to safely and effectively fluoridate drinking water, Palmer said.
Wellington Water has apologised for the failure and committed to implementing all the findings of the review.
The company is working towards returning fluoridation to the two plants where it was switched off by September this year.
Royal New Zealand College of General Practitioners medical director Dr Bryan Betty said there could be an upswing in tooth decay.
“Tooth decay in children is a very large issue. It’s one that we confront on a daily basis, it’s one that we see on a daily basis, especially in the Porirua basin.
“Preventative measures like fluoridation in the water, brushing your teeth twice a day, and drinking less sugary drinks are fundamentally important to the health of children’s teeth.”
New Zealand Dental Association spokesman Dr Rob Beaglehole said it was a dental disaster.
He said people living in deprivation, who don’t brush their test daily with fluoride toothpaste, and those who excessively consume sugary drinks were most likely to be affected.
“They may be experiencing higher levels of new dental decay and that experience may also be more severe.
Hutt South MP Ginny Andersen told Newstalk ZB Wellington Mornings host Nick Mills her youngest child had just turned 8.
“So, for the bulk of the years of her life, I’ve been thinking as a parent that she’s been drinking water with fluoride in it when she hasn’t.”
National list MP Chris Bishop said it was a shocking failure on multiple levels.
The review also found there was no documentation setting out service-level expectations for optimal fluoridation between the regional council, which owns the bulk water supply assets, and Wellington Water.
Council chairman Daran Ponter said the relationship between the two parties will have to be made more specific than one based more broadly on trust and confidence.
“It (the fluoride failure) does affect your confidence, because it now raises the question of what else?”
The council has already confirmed it will introduce a key performance indicator for fluoridation.
Asked whether people in leadership roles at Wellington Water should keep their jobs, Ponter said the council would meet to consider whether there should be any consequences at a board level.
Current Wellington Water board chairwoman Lynda Carroll is a relatively fresh face to the organisation.
She was appointed to the board in June 2021 and took over as chairwoman in November.