23 January 2026
LGOIMA 25-237
Sharna
[FYI request #32674 email]
Tēnā koe Sharna,
Community water fluoridation
I refer to your request to the Ministry of Health – Manatū Hauora for information about community water
fluoridation. On 5 December 2025, part of your request (questions 1, 11, and 12) were transferred to
Wellington Water Limited under section 12 of the Local Government Official Information and Meetings
Act 1987 (LGOIMA). This is because Wellington Water may hold this information on behalf of the
Wellington region’s councils as their water services provider.
It has also been identified that additional questions (3, 7, and 18) from your request to the Manatū
Hauora can be addressed by Wellington Water Limited. Our responses to these questions are provided
below in accordance with the requirements of the Act.
Identify the factory/facility where the fluoride chemicals supplied to New Zealand water
1.
systems are produced, including location, operator, and production process. Include all
applicable laws, regulations, licenses, and international standards governing manufacture.
Provide the full chemical composition, including chemical names, chemical formulae, and
3.
concentrations of all fluoride compounds added to the public water supply.
Clarify whether New Zealand currently manufactures fluoride chemicals domestically, imports
7.
ready-made fluoride chemicals, or both, including details of manufacturers and import
sources.
Identify all contractors, consultants, and water treatment personnel who handle, dose, or
11.
monitor fluoride chemicals.
Contractors & Distribution: Provide full contract details, including terms of service, duration,
12.
performance bonds, insurance coverage, and any professional certifications required
Disclose any incidents, complaints, or breaches relating to fluoride chemical safety,
18.
handling, or dosing.
Wellington Water adds fluoride to water at four of the water treatment plants we manage on behalf of
Greater Wellington Regional Council. These are Te Mārua, Wainuiomata, Waterloo and Gear Island Water
Treatment Plants.
Wellington Water must maintain a steady level of fluoride in the water at water treatment plants to meet
the Ministry of Health fluoride target levels of 0.7 – 1.0ppm, 95% of the time to provide public with oral
health benefits.
Wellington Water must also never supply customers with drinking water with fluoride over the Maximum
Acceptable Value of 1.5ppm and we have controls in place to do this.
The Ministry of Health guidelines also require that 95 per cent of the water leaving all water treatment
plants meet target levels.
Wellington Water Limited uses two chemicals for water treatment:
Hydrofluorosilicic Acid (HFA): H₂SiF₆
Sodium Silicofluoride (SSF): Na₂SiF₆
Ballance Agri-Nutrients Limited is the legal name of the company that manufactures HFA and
supplies it to IXOM. Wellington Water procures HFA from IXOM.
Sodium Silicofluoride (SSF) is sourced by IXOM from either Prayon or Shimonoseki Mitsui, depending
on product availability and supply chain considerations
For further details, please refer to the
SSF Factsheet from IXOM, which outlines the supply, manufacture,
quality, and safety of fluoride products in New Zealand. These companies comply with the Hazardous
Substances and New Organisms Act (HSNO Act), requiring Environmental Protection Authority (EPA)
approval and WorkSafe New Zealand certifications for handlers, equipment, and storage.
The
Good Practice Guide: Supply of Fluoride for Use in Water Treatment , published by Water New Zealand,
sets out the physical, chemical, and testing requirements for fluoride used in water treatment.
Specific information about fluoride use in the Wellington potable water network can be found at:
Monitoring Fluoride Levels At Water Treatment Plants
Fluoride At Water Treatment Plants
Weekly Fluoride Project Updates
11.
Identify all contractors, consultants, and water treatment personnel who handle, dose, or monitor
fluoride chemicals.
This information is withheld under section 7(2)(a) – to protect the privacy of natural persons. The public
interest in accountability and transparency has been considered. However, this is adequately met through
published regulatory requirements, operational controls, and independent auditing of drinking water safety.
Releasing the names or identities of individual personnel would not materially advance public understanding
and would unreasonably infringe personal privacy.
12.
Contractors & Distribution: Provide full contract details, including terms of service, duration,
performance bonds, insurance coverage, and any professional certifications required.
Wellington Water Limited does not hold the details of these contractors or distributors. Accordingly, this
part of your request is refused under section 17(e) of the Local Government Official Information and
Meetings Act 1987, as the information is not held.
18.
Disclose any incidents, complaints, or breaches relating to fluoride chemical safety, handling, or
dosing.
2/2/2024: While replacing a pump in the HFA dosing area at Gear Island, a valve was accidentally activated,
causing the mixed solution to spray over two workers. Another team member quickly assisted them to
remove their PPE and use the emergency shower for 20 minutes, after which they applied Calcium
Gluconate Gel. Both staff were assessed by a doctor and were cleared later that day.
I also refer you to the publicly available information:
Fluoride Independent inquiry 2022
Media release:
Low fluoride levels in drinking water for Central Lower Hutt and Parts of
Wellington City – 2024
Media release:
Brief Spike In Fluoride Levels At The Waterloo Water Treatment Plant No Cause
For Public Health Concerns - 2025
Wellington Water Limited proactively publishes all LGOIMA responses regarding fluoride on its
website. To view these, visit
www.wellingtonwater.co.nz and search “fluoride,” or use this direct
link:
Fluoride search.
Additionally, we publish all fluoride outages on our website on social media channels when they occur.
Your response will be published on our website at
www.wellingtonwater.co.nz/about-us/official-
requests/official-information-act-responses, with any personal information removed.
You have the right to seek an investigation and review of this response by the Ombudsman. Information
about how to make a complaint is available at www.ombudsman.parliament.nz or by calling 0800 802 602.
If you would like to discuss this response, please contact us at
[email address]
Nāku noa, nā
Jeremy McKibbin
Group Manager
Treatment and Control Systems
