Fluoridated drinking water for up to 100,000 Northlanders could be coming out of their taps within 18 months.

Last July then Director General of Health Dr Ashley Bloomfield ordered Government-mandated fluoridation for council drinking water plants servicing Whangārei, Bream Bay, Kaitāia and Kerikeri and affecting 65,250 people.

In November the Government indicated further mandated fluoridation was in its sights for more Far North drinking water supplies including those for Kaikohe, Kawakawa, Moerewa, Ōkaihau, Ōpononi, Paihia and Rawene – potentially affecting another 14,180 people.

It has also asked for high-level fluoridation cost estimates for two Kaipara council drinking water supplies, but has not yet mandated the chemical’s addition to any of its supplies. Adding fluoridation to council-supplied Dargaville and Maungaturoto drinking water would add a further 7600 affected people into the mix.

None of Northland’s 17 council drinking water supplies are currently fluoridated, but the first public drinking water supply in the region is likely to have industrially produced fluoride within 18 months.

The Government says the Whangārei District Council (WDC) and the Far North District Council (FNDC) have until July 2024 to start putting fluoride into the seven water treatment plants that were part of the July 2021 Government order.

If fluoridation goes ahead, councils will be using New Zealand-made industrial fluoride in the form of fluosilicic acid, also known as hydrofluosilicic acid.

Hydrofluosilicic acid is produced during the manufacture of superphosphate fertiliser. It is the form of fluoride most widely used by NZ councils, and is added into drinking water as a liquid.

WDC and FNDC have told the Government it will cost more than $5 million to fluoridate their July-mandated water treatment plants – WDC $3.75 million and FNDC $1.32 million.

They are among 14 councils that were mandated to fluoridate in July which will be competing for the Government’s $11.3 million Manatū Hauora Ministry of Health fund. This was set up for councils for drinking water fluoridation introduction costs. The two Northland councils’ costs alone amount to more than 40 per cent of the available money.

WDC water services manager Andrew Venmore said his council was waiting to hear back from Manatū Hauora about funding and WDC’s fluoridation start date was funding dependant.

Venmore said once funding was secured, it could be as soon as 18 months for fluoridation to kick in for the council’s Whau Valley and Ruddells water treatment plants, 24 months for the Ahuroa and Ruakākā water treatment plants and 42 months for the council’s Poroti treatment plant.

The council would have to “seek funding from within our own resources” if government funding was not available or enough for the job to be done, Venmore said.

WDC would also have to spend $100,000 annually to run its fluoridated drinking water supplies, he said.

WDC would have a fluoridation dose rate target of .85mg/l.

FNDC manager infrastructure operations Glenn Rainham said fluoridating the Kerikeri and Kaitāia plants would add another $42,000 of annual council operating cost on top of the initial capital outlay. There would be more costs on top of that if other treatment plants were mandated.

“If a new direction order is given, it is the council’s understanding that the cost will be met by new water entities planned by the Government,” Rainham said.

KDC operations manager infrastructure services Donnick Mugutso said his council had not been mandated to add fluoride to its Dargaville and Maungaturoto drinking water supplies.

He said KDC had done initial high-level fluoridation implementation cost estimates as requested by the Ministry of Health. It would do more detailed costings if directed to fluoridate.

KDC has told the Government it would take about three years to bring in fluoridation – if a direction was given and funding was available. The council would seek Manatū Hauora funding if told to fluoridate.

“We would seek as much as could be allocated, to relieve any potential cost impact fluoridating water supplies would have on our ratepayers,” Mugutso said.

Mandated fluoridation for KDC water treatment plants would affect more than 11,000 people. More than 70 per cent of Kaipara is on private water supply.

■ Local Democracy Reporting is Public Interest Journalism funded through NZ On Air