Community Water Fluoridation in Wellington & Taranaki

About this project

In early 2024 a private member's bill (the Fluoridation Referendum Bill) was proposed to reverse a 2021 Act that had moved fluoridation decision-making from local councils to the Director-General of Health. In practice, reverting to local control would have meant some councils discontinuing fluoridation in their water supplies, with predictable population health consequences.

This HIA was prepared in the role of an analyst supporting Te Āti Awa, whose rohe spans both Wellington and Taranaki. The job was to evaluate the population health consequences of the proposed change and to ground the submission in a structured assessment of risks, benefits, and equity impacts.

Approach

The HIA followed the standard structure set out in the Ministry of Health's Guide to Health Impact Assessment: screening, scoping, and assessment of impacts. The geographic scope was narrowed to Wellington and Taranaki, in line with Te Āti Awa's area of interest.

It was paired with an Environmental Health Risk Assessment appendix that worked systematically through hazard identification (for both the presence and absence of fluoride), dose-response, exposure assessment, risk characterisation, and risk management, drawing on the WHO drinking water quality guidelines and the 2014 Royal Society of New Zealand review. The dual structure was deliberate: HIA captures the population health and equity story, EHRA grounds it in the underlying toxicological evidence. Together they create a submission that is much harder to dismiss.

Key findings

• Removing fluoride from community water supplies would predictably increase dental caries prevalence, with disproportionate effects on populations who already face significant barriers to accessing dental care, particularly Māori and Pasifika children.
• Year 8 oral health data shows higher caries-free rates in fluoridated regions, and the gap is larger for Māori and Pasifika children than for non-Māori non-Pasifika children. Removing fluoride therefore widens rather than narrows existing oral health inequities.
• The intervention is unusually low-friction: it operates at the water-supply level rather than at the level of individual behaviour, which is why its protective effect is strongest for populations with the least access to dental services.
• Removing universal protective coverage without simultaneously providing free or universal access to dental services would represent a breach of the Crown's obligations under Te Tiriti o Waitangi, particularly the principles of equity (Article 3) and active protection (Article 2).
• The assessment recommended retaining centralised decision-making under the Director-General of Health, rejecting the Fluoridation Referendum Bill, and applying a Te Tiriti o Waitangi lens to all subsequent oral health policy decisions.

What this project demonstrates

This is the kind of work I could do for a public health team, a Crown agency, an iwi-led organisation, or a regulatory consultancy producing analytical submissions on contested policy. The skills behind it are health impact assessment and environmental health risk assessment used together, evidence synthesis from regulatory and scientific sources, use of Te Tiriti o Waitangi to guide the analysis in a practical and meaningful way, and the ability to translate technical risk assessment into language a parliamentary committee can actually use. It transfers naturally to policy, regulatory affairs, public health programmes, and Crown or iwi advisory work.