Water Fluoridation and Informed Consent

Almost every argument about water fluoridation is an argument about science — how much fluoride is too much, whether it lowers IQ, how many cavities it actually prevents. This page is about a different question, one that does not resolve even if the science comes out entirely in fluoridation's favour: who decided, and were you asked?

The distinction that drives the whole dispute is a simple one. Chlorine is added to water to treat the water — to kill bacteria and make it safe to drink. Fluoride is added to treat the person — a medical intervention meant to prevent tooth decay in whoever drinks it. Everything else follows from that difference, and from what the law has and has not been willing to do about it.

One thing should be said plainly at the outset, because it is the point on which this argument is most often overstated: no court anywhere has held that water fluoridation violates human rights law. What follows is an ethical argument with real and growing legal momentum behind it — not a settled legal conclusion.

Table of Contents

  1. Cardozo and the Right to Refuse
  2. Nuremberg, UNESCO and Oviedo
  3. The Consent Argument in Full
  4. The Netherlands, 1973
  5. Ireland, 1965
  6. Police Power and the Salt Analogy
  7. The Federal Case, 2024–2026
  8. Utah, Florida and the 2026 Wave
  9. The Case Against This Argument
  10. Where This Actually Stands
  11. Key Research Papers
  12. Connections
  13. Featured Videos

Cardozo and the Right to Refuse

In 1914, Justice Benjamin Cardozo of the New York Court of Appeals decided a case brought by Mary Schloendorff, who had consented to an examination under anaesthesia but explicitly refused an operation, and woke to find a tumour had been removed. Her hand later became gangrenous and she lost several fingers.

Cardozo's sentence in that judgment became the foundation of modern informed-consent doctrine throughout the English-speaking world:

“Every human being of adult years and sound mind has a right to determine what shall be done with his own body; and a surgeon who performs an operation without his patient's consent commits an assault, for which he is liable in damages.” — Schloendorff v. Society of New York Hospital, 211 N.Y. 125 (1914)

Two things about the case are worth knowing, because both are routinely lost when the quotation is used. First, Mrs. Schloendorff lost — the hospital was held to be a charitable institution not liable for the negligence of its physicians, a doctrine long since abandoned. The famous sentence is what lawyers call dicta: reasoning that was not strictly necessary to the outcome. Second, and despite that, it has been quoted and applied for more than a century, because it stated a principle the law had not yet articulated so cleanly. The right to refuse treatment is now understood to be near-absolute for a competent adult, even where refusal is medically catastrophic and even where the refusal seems irrational to everyone else.

The consent argument against fluoridation asks a straightforward question: if that principle is real, how does adding a substance to the public water supply for the purpose of preventing a disease escape it?

Cardozo's principle did not stay in New York. It was absorbed into the international instruments written after the Second World War and after the medical scandals of the twentieth century, and those instruments state it in broader terms than a surgical case required.

These are the principled anchors that critics of fluoridation cite, and they are genuine, quotable, and on point in their wording. What they are not is enforced. No tribunal has been persuaded to read any of them as prohibiting the fluoridation of a public water supply. Presenting them as though they settle the question is the single easiest way to have the whole argument dismissed.

The Consent Argument in Full

Stated at its strongest, without the legal overreach, the argument runs like this.

  1. Fluoridation is an intervention on people, not on water. Chlorination, filtration and pH adjustment all treat the water itself — they make the delivered product safe or palatable. Fluoride does nothing to the water. Its entire purpose is a pharmacological effect in the body of the person who drinks it: the strengthening of tooth enamel against decay. That is the definition of a preventive medical intervention.
  2. There is no dose control. Every other medicine is prescribed by dose. Fluoridation sets a concentration — 0.7 mg/L in the United States — and the dose each person receives is whatever their water consumption happens to be. An outdoor labourer in Arizona drinking four litres a day receives many times the dose of a sedentary office worker drinking one. Infants fed formula reconstituted with fluoridated water receive a high dose relative to body weight, which is why several health agencies now advise using low-fluoride water for formula.
  3. It cannot be individualised. People with impaired kidney function excrete fluoride less efficiently. People with iodine deficiency or thyroid disease may be more susceptible to its effects on thyroid function. A prescriber would take these into account. A water utility cannot.
  4. Refusal is expensive rather than free. This is the part that distinguishes fluoridation from most public-health measures. You can decline a vaccine by not attending an appointment. Declining fluoridated water means installing reverse-osmosis or activated-alumina filtration, or buying bottled water indefinitely — a cost falling hardest on exactly the low-income households fluoridation is most often justified as protecting. The Dutch Supreme Court, as it happens, found this reasoning persuasive (below).
  5. Nobody is asked. There is no consent form, no discussion of risks and benefits, and in most jurisdictions no individual vote. The decision is made by a utility, a city council or a state legislature.

Note what this argument does not require. It does not require fluoride to be harmful. It does not depend on the IQ literature being right. A person who accepts that fluoridation is entirely safe and modestly beneficial can still hold that it is administered in a way that no other medicine is.

The Netherlands, 1973

The strongest court decision in favour of this position is Dutch, and it is worth being precise about what it did and did not say.

On 22 June 1973 the Hoge Raad — the Supreme Court of the Netherlands — decided a case brought against the City of Amsterdam (Budding and co. v. City of Amsterdam, ECLI:NL:HR:1973:AD2208). The court held that fluoridating drinking water was so far-reaching a measure that it required a specific legal basis, and that the Water Supply Act did not provide one. Nothing in the statute suggested that water companies had been authorised to add substances for a purpose unrelated to water quality.

The reasoning is directly relevant to the consent argument even though the court never used the word. The Hoge Raad observed that water companies hold a monopoly in their distribution area, and that drinking water is one of life's first necessities — so consumers are effectively forced to consume whatever has been added to it. That is the “no practical way to refuse” point, stated by a supreme court, eleven years before most of the modern literature on the subject.

What happened next matters as much as the ruling. Parliament began drafting an amendment to the Water Supply Act that would have supplied the missing legal basis. During the process it became clear the amendment lacked parliamentary support, and in 1976 the bill was withdrawn. No fluoride has been added to Dutch tap water since.

So the Netherlands is not an example of a court finding fluoridation to be a human-rights violation. It is an example of a court insisting that a measure this intrusive requires explicit democratic authorisation — and of a parliament then declining to give it. That is a narrower holding, and a more durable one.

Most of continental Europe never adopted water fluoridation at all. Several countries — Germany, Switzerland, Austria and France among them — instead make fluoridated salt available alongside ordinary salt in shops. Whatever its merits dentally, that arrangement has an obvious property: the person choosing between two packets on a shelf is exercising consent.

Ireland, 1965

The Irish case is frequently cited on both sides of this argument, usually inaccurately, and it repays being read properly.

Gladys Ryan, a Dublin mother of five, challenged the constitutionality of the Health (Fluoridation of Water Supplies) Act 1960. Represented by Seán MacBride SC, she argued that fluoridating the public supply infringed her personal rights under Article 40.3 of the Irish Constitution because it removed her choice. The case reached the Supreme Court in 1965.

She lost — and in losing, won something larger. Kenny J. held that the personal rights guaranteed by Article 40.3 were not confined to those the Constitution happened to list, and that there existed further “unenumerated” rights implied by it. Among them, he held, was a constitutional right to bodily integrity. Ryan v. Attorney General [1965] IR 294 is to this day the founding authority for unenumerated constitutional rights in Irish law, and the case in which the right to bodily integrity was first recognised there.

Mrs. Ryan's claim nonetheless failed, on the facts rather than the principle: the court held that she had not proved fluoridation of water at the levels used was harmful to health. The right existed; the evidence did not establish that this particular measure infringed it.

This is why the case is a poor authority for the proposition that fluoridation was found lawful in principle, and an equally poor one for the proposition that bodily integrity defeats fluoridation. It established a right and then declined to apply it for want of proof of harm — which places the whole question back onto the scientific evidence, exactly where the pure consent argument was trying to avoid going.

Police Power and the Salt Analogy

American courts have taken a consistently different route, and it is the reason the consent argument has made so little headway in United States litigation.

The governing idea comes from Jacobson v. Massachusetts, 197 U.S. 11 (1905), which upheld a compulsory smallpox vaccination ordinance against a liberty challenge. The Supreme Court held that individual liberty is not absolute and may yield to reasonable regulations enacted to protect the common good — the state's “police power.” That framework has been applied to fluoridation by state courts repeatedly since the 1950s, and challenges have essentially uniformly failed.

Alongside it sits an analogy that does a great deal of work: fortification. Iodine is added to salt to prevent goitre and cretinism. Folic acid is added to flour to prevent neural-tube defects. Vitamin D is added to milk to prevent rickets. Each is a substance added to a common good for the purpose of producing a health effect in the population, none obtains individual consent, and none is generally regarded as a human-rights problem. On this view fluoridation is nutritional fortification of a public resource, not treatment of an individual, and the consent framework simply does not apply.

The counter-argument is that the analogy breaks at the point of refusal, and that this is not a technicality. Unfortified salt, flour and milk are all available in any supermarket at ordinary prices. There is no unfluoridated tap. A person who wishes to avoid iodised salt changes brands; a person who wishes to avoid fluoridated water changes their plumbing. Whether that difference is constitutionally significant has, so far, been answered by American courts in the negative — but it has rarely been litigated squarely on consent grounds, because plaintiffs have generally chosen to argue harm instead.

The Federal Case, 2024–2026

The most consequential fluoridation litigation in decades took the harm route, under an environmental statute rather than a constitutional one — and its history is a caution against reading too much into any single headline.

The 2024 ruling. In Food & Water Watch, Inc. v. U.S. Environmental Protection Agency, brought as a citizen petition under section 21 of the Toxic Substances Control Act, Judge Edward Chen of the Northern District of California ruled on 24 September 2024 that fluoridation at the HHS “optimal” level of 0.7 mg/L poses an unreasonable risk of reduced IQ in children, and ordered EPA to initiate rulemaking under TSCA section 6(a). It was the first TSCA citizen petition ever to reach trial and prevail. The case had an unusual procedural history: a seven-day trial in 2020, then a hold pending the National Toxicology Program's systematic review, then a second trial in 2024 at which that review was in evidence.

It is important to be exact about what the ruling meant. An “unreasonable risk” finding under TSCA is a regulatory trigger requiring EPA to act; it is not a finding that fluoridation is unlawful, and the court did not order fluoridation to stop.

The 2026 reversal. On 21 May 2026 the Ninth Circuit filed a memorandum disposition vacating that decision and remanding the case. The panel held that the district court had abused its discretion by “commandeering” the proceedings — principally by holding the case in abeyance after the first trial and then deciding it on a record that had grown to include material neither party had presented at that first trial. On remand, Judge Chen must determine whether the plaintiffs have standing and, if so, whether the original trial record supports an unreasonable-risk finding.

Two details matter for anyone weighing this. The Ninth Circuit's opinion did not address the factual merits of the risk finding — the reversal was procedural. And EPA's appeal was itself framed on procedural grounds rather than contesting the substance of the risk determination. Neither of those facts means the risk finding was correct; they mean it has not yet been tested on appeal. The plaintiffs' attorney, Michael Connett, has indicated the plaintiffs are weighing further review.

As of August 2026 the matter is back before the district court and undecided.

Utah, Florida and the 2026 Wave

While the federal case moved through the courts, the argument moved into legislatures — and there, unlike in court, it was framed explicitly in terms of consent.

Utah became the first state to ban fluoridation of public drinking water when Governor Spencer Cox signed H.B. 81 on 27 March 2025. The law also added fluoride to the list of medications a pharmacist may prescribe, which is a revealing piece of drafting: it removes fluoride from the water while keeping it available to anyone who chooses it. The bill's sponsor, Representative Stephanie Gricius, put the rationale in one sentence — “Why would we put a prescription into somebody's drinking water without their consent?”

Florida followed when Governor Ron DeSantis signed S.B. 700 on 15 May 2025, effective 1 July 2025. DeSantis described fluoridation as “forced medication” and said that “at the end of the day, we should all agree that people deserve informed consent.” That is Cardozo's principle, invoked by name in all but the citation. The Florida law restricts what local governments may add to public water; it does not prevent anyone from buying fluoridated water or fluoride products privately.

Since the start of 2026, lawmakers in at least fifteen states have introduced bills prohibiting or limiting fluoride in public water. Separately, bills to repeal existing state fluoridation mandates have been introduced in nine of the twelve states that have them — Ohio, Kentucky, Georgia, Minnesota, Mississippi, South Dakota, Arkansas, Louisiana and Nebraska — several with bipartisan sponsorship.

At municipal level the shift has been faster than at state level. The Fluoride Action Network, an advocacy organisation that campaigns against fluoridation and whose figures should be read with that in mind, counted 62 communities serving more than nine million people ending, suspending or rejecting fluoridation between September 2024 and April 2025, with substantially higher cumulative figures since.

Federal review. On 22 January 2026 the EPA released a Fluoride Human Health Toxicity Assessment: Preliminary Assessment Plan and Literature Survey for public comment — the first step of a new health assessment the agency has described as a “gold standard” review, following an April 2025 directive from Administrator Lee Zeldin to expedite the next assessment. The plan sets out how EPA intends to evaluate the evidence and explicitly identifies infants and children as sensitive populations. Comment closed on 27 February 2026; the assessment itself has not been published.

The Case Against This Argument

An argument is only worth as much as its treatment of the strongest objections, and there are several here that deserve better than dismissal.

The fortification analogy is genuinely strong. If adding fluoride to water is mass medication, then so is adding folic acid to flour — and folic acid fortification prevents a devastating birth defect in people who never consented to it either. Very few of fluoridation's critics call for the repeal of folic acid fortification. If the principle is to be applied consistently, it has consequences that most people who invoke it have not accepted.

The evidence for neurological harm at United States levels remains contested. The National Toxicology Program's August 2024 monograph concluded “with moderate confidence” that higher fluoride exposure is associated with lower IQ in children — but it defined higher exposure as more than 1.5 mg/L, roughly double the 0.7 mg/L used in United States fluoridation, and it expressly stated that more studies are needed to understand whether lower exposures affect IQ. That distinction is routinely dropped when the monograph is cited, and dropping it is a misrepresentation of the source.

The strongest United States cognitive study to date found nothing. In April 2026, Warren and colleagues published in PNAS an analysis of the Wisconsin Longitudinal Study — 10,317 people who graduated from Wisconsin high schools in 1957, with childhood fluoridation exposure estimated from residence up to age 14, adolescent IQ from tests administered in school, and adult cognition measured at four points up to age 80. It found no evidence that community water fluoridation was negatively associated with adolescent IQ or with adult cognitive function. It is the first United States study to follow childhood fluoridation exposure through to late-life cognition, and it cuts directly against the findings relied on in recent decisions to end fluoridation.

Its limitations are real and should be stated alongside it: the cohort is a single-state, overwhelmingly white 1957 graduating class; exposure was estimated from place of residence rather than measured in individuals; and total fluoride intake in the 1940s and 1950s came overwhelmingly from water, whereas today it also comes from toothpaste, processed food and dental products. It is nevertheless the most rigorous study of its kind conducted in the United States, and an honest treatment of this subject has to sit with that.

Public-health law has never required individual consent. Quarantine, food-safety regulation, air-quality standards and compulsory water treatment all constrain individuals without asking them. A principle that treats any population-level health measure as requiring personal consent would dismantle a great deal more than fluoridation.

There is, however, one objection that has weakened rather than strengthened — and it belongs to the benefit side of the ledger. The Cochrane Collaboration's 2024 review of water fluoridation, covering 157 studies, found that trials conducted before 1975 showed a clear and important reduction in tooth decay, but that contemporary studies show much smaller effects, because fluoride toothpaste is now nearly universal. In the contemporary studies analysed, fluoridation was estimated to produce on average about 0.24 fewer decayed baby teeth per child. That is not nothing, but it is far from the figures still quoted in campaign material on both sides.

This matters to the consent question specifically. The legal justification for overriding individual choice under the police power is proportionate to the size of the public benefit. A benefit that has shrunk by an order of magnitude since the policy was adopted does not make fluoridation unlawful — but it does weaken the state's side of the balance without requiring anyone to prove harm at all.

Where This Actually Stands

Pulling the threads together, and being careful about what is established and what is not:

The honest summary is that Cardozo's principle has not been applied to what governments may add to the water everyone has to drink, and that the question of whether it should be is now being decided in legislatures rather than courts. Whether that is the right forum is itself a fair question — consent is normally a right that protects individuals against majorities, and a majority vote to stop fluoridating is not obviously a vindication of it.

What a reader can do with this is narrower but concrete. You can find out whether your own supply is fluoridated and at what concentration, which is public information in most jurisdictions. You can measure your own water. And if you would rather not consume it, the practical options are set out on the main fluoride page under how to reduce fluoride exposure and testing your water. Those remain, for now, the only reliable form of opting out.

Key Research Papers

Every citation below has been checked against the publisher's own record. Legal citations link to primary or authoritative secondary sources.

Fluoride, neurodevelopment and cognition

  1. National Toxicology Program. NTP Monograph on the State of the Science Concerning Fluoride Exposure and Neurodevelopment and Cognition: A Systematic Review. NTP Monograph 08, August 2024 (PMID 39172715). Moderate confidence of association with lower childhood IQ at exposures above 1.5 mg/L.
  2. Warren JJ, Rumore G, Sicinski K, Herd P, Engelman M. Municipal water fluoridation, adolescent IQ, and cognition across the life course: Evidence from the Wisconsin Longitudinal Study. Proceedings of the National Academy of Sciences, 123(16), 13 April 2026. No association found at United States fluoridation levels.
  3. Grandjean P, Landrigan PJ. Neurobehavioural effects of developmental toxicity. The Lancet Neurology, 13(3):330–338, 2014. The paper that placed fluoride on a list of developmental neurotoxicants.
  4. Choi AL, Sun G, Zhang Y, Grandjean P. Developmental Fluoride Neurotoxicity: A Systematic Review and Meta-Analysis. Environmental Health Perspectives, 120(10):1362–1368, 2012. Largely high-exposure Chinese cohorts, a limitation acknowledged by the authors.
  5. Bashash M, Quissán D, Tellez-Rojo MM, et al. Prenatal Fluoride Exposure and Cognitive Outcomes in Children at 4 and 6–12 Years of Age in Mexico. Environmental Health Perspectives, 125(9):097017, 2017.
  6. Green R, Lanphear B, Hornung R, et al. Association Between Maternal Fluoride Exposure During Pregnancy and IQ Scores in Offspring in Canada. JAMA Pediatrics, 173(10):940–948, 2019.

Dental benefit

  1. Iheozor-Ejiofor Z, Walsh T, Lewis SR, Riley P, Boyers D, Clarkson JE, Worthington HV, Glenny A-M, O'Malley L. Water fluoridation for the prevention of dental caries. Cochrane Database of Systematic Reviews, Issue 10, 2024 (PMID 39362658). 157 studies; benefit substantially smaller in the post-1975 era of fluoride toothpaste.

Legal sources

  1. Schloendorff v. Society of New York Hospital, 211 N.Y. 125, 105 N.E. 92 (1914) — case overview.
  2. Jacobson v. Massachusetts, 197 U.S. 11 (1905) — full opinion, Justia.
  3. Ryan v. Attorney General [1965] IR 294 (Supreme Court of Ireland) — judgment. Recognised the unenumerated constitutional right to bodily integrity; challenge to the Health (Fluoridation of Water Supplies) Act 1960 dismissed on the evidence.
  4. Hoge Raad, 22 June 1973, ECLI:NL:HR:1973:AD2208 (Fluoridering / Budding v. City of Amsterdam) — background and aftermath.
  5. UNESCO. Universal Declaration on Bioethics and Human Rights, 2005 — Article 6, prior free and informed consent.
  6. Council of Europe. Convention on Human Rights and Biomedicine (Oviedo Convention, ETS 164), 1997 — Article 5.
  7. Food & Water Watch, Inc. v. U.S. EPA, N.D. Cal., findings of fact and conclusions of law, 24 September 2024; vacated and remanded, 9th Cir., 21 May 2026 — appellate summary.
  8. Utah H.B. 81, Fluoride Amendments (2025) — bill text, Utah Legislature.
  9. U.S. EPA. Review of Science on Fluoride in Drinking Water: Preliminary Assessment Plan and Literature Survey, Federal Register, 28 January 2026.

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