Wellington's water service apologises after damning review into lack of fluoridation

"Fluoridation wasn't a priority for Wellington Water."

That's the verdict of an independent inquiry into why fluoridation was turned off at two water treatment plants last year and it's still months until it will be turned back on.

Wellington Water's chief admitted a failure.

"I would like to apologise on behalf of Wellington Water to the people of Wellington. We had a responsibility to put fluoride into your water and we did not do that consistently," Wellington Water chair Lynda Carroll said.

The principal dentist at Caring 4 Smiles Dental Group Dr Loy Correa knows all too well what happens when teeth are not looked after.

Fluoride in drinking water is a key tool to prevent tooth decay.

"It actually changes the molecular structure of enamel and dentin making it less soluble," Dr Correa said.

In other words, it stops your teeth from rotting.

Council-owned Wellington Water revealed in March it had turned off fluoridation at two treatment plants over storage facility concerns and issues with dosage.

It said it was for a month, but the board later admitted it actually stopped fluoridation at one of the facilities in May last year and it's still not happening.

"It is unacceptable to leave out pockets within a city," Dr Correa said.

An independent investigation has revealed there were no plans to turn fluoridation back on and Wellingtonians weren't informed.

"That is unacceptable," Carroll said.

The inquiry has found that "fluoridation for oral health wasn’t a priority for Wellington Water".

It also found that "across all the water treatment plants fluoride concentrations were frequently below the optimal level" and "the board didn't have the technical expertise".

"Possibly tens of thousands of Wellingtonians have been drinking water that hasn't been fluoridated for up to 18 months," NZ Dental Association spokesperson Dr Rob Beaglehole said.

Wellington Water's board says it's committed to meeting the report's recommendations, including making sure it has the right "collective expertise" and has a "relentless focus on fluoridation".

The bad news for Wellingtonians is that fluoride won't be back in drinking water until September.

"It's an appalling situation," Dr Beaglehole said.

Because it's fluoride that helps make trips to the dentist rare.