Federal Fluoride Ruling Vacated: Where the EPA Case Stands in 2026
A federal court decision on fluoride in drinking water drew national attention in late 2024. In May 2026 an appeals court threw that decision out on procedural grounds and sent the case back to the trial judge. This article covers what the original ruling said, what the appeal changed, the research at the center of the dispute, and practical steps for lowering fluoride intake if you choose to.
Key Takeaways
- In September 2024, Judge Edward Chen found that fluoridating water at 0.7 mg/L poses an unreasonable risk of reduced IQ in children under the Toxic Substances Control Act, and ordered the EPA to respond with regulation.
- On May 21, 2026, the Ninth Circuit vacated that ruling because of how the trial court managed the case. The panel did not rule on the science either way. The case is back before the district court.
- The National Toxicology Program review behind the case linked fluoride exposure at 1.5 mg/L and above with lower IQ scores in children. US water systems fluoridate at 0.7 mg/L, about half that level.
- Reverse osmosis, activated alumina, and distillation remove most fluoride from tap water. Standard carbon pitcher filters do not.
- Fluoride's dental benefit is primarily topical. Toothpaste that is spit out delivers it without the swallowed dose.
This article is for educational purposes only and is not medical advice. Talk with a qualified healthcare provider before changing your health routine.
The 2024 ruling
Evidence: federal court record, primary documents.
The case, Food & Water Watch v. EPA, began as a 2016 citizen petition asking the EPA to ban the addition of fluoride to drinking water under Section 21 of the Toxic Substances Control Act. The EPA denied the petition and the plaintiffs sued. After two bench trials, Judge Edward Chen of the Northern District of California ruled on September 24, 2024 that fluoridation at 0.7 mg/L, the level considered optimal in the United States, poses an unreasonable risk of reduced IQ in children, and ordered the EPA to address that risk.1
Chen was careful about the scope of his finding. His order states that it does not conclude with certainty that fluoridated water injures public health. TSCA requires a lower bar: an unreasonable risk of injury, enough to obligate a regulatory response.1 The distinction matters when reading coverage of the case, because the ruling identified a risk to be managed rather than a proven harm.
The scientific centerpiece was the National Toxicology Program monograph on fluoride and neurodevelopment. NTP concluded with moderate confidence that fluoride exposures at or above 1.5 mg/L are associated with lower IQ in children.2 That is about twice the US fluoridation level of 0.7 mg/L and well below the EPA's enforceable cap of 4 mg/L. The trial then turned on whether the margin between 1.5 and 0.7 is wide enough to be safe, and the judge found it was not, given variation in individual water intake and exposure from other sources.
What the appeal changed in 2026
Evidence: federal court record, primary documents.
The EPA appealed in January 2025 and continued the appeal under the new administration, arguing legal error rather than attacking the scientific findings. On May 21, 2026, the Ninth Circuit vacated the district court's decision and remanded it.3 The panel held that the trial judge overstepped by taking control of the case after the first bench trial, pausing it for years to wait for the NTP report, and shaping what evidence came in. Under the party-presentation principle, those choices belong to the litigants.
The appellate decision is narrow. It did not decide whether fluoride at 0.7 mg/L presents an unreasonable risk, and it did not reject the NTP findings. It rejected the process. The plaintiffs' claims are now back before the district court, and the scientific question remains legally unresolved. Under the usual Safe Drinking Water Act schedule, the next federal scientific review of the fluoride standard is not due until 2030, so this litigation remains the fastest-moving venue for the issue.
Fluoride and sleep
Evidence: one cross-sectional human study.
One published study has examined fluoride exposure and sleep directly. Malin and colleagues analyzed NHANES 2015 to 2016 data on adolescents aged 16 to 19 and found that each 0.52 mg/L increase in household water fluoride was associated with 1.97 times the odds of symptoms suggestive of sleep apnea, along with later bedtimes and wake times.4 The design was cross-sectional and the sleep outcomes were self-reported, which means the study can show an association but cannot show that fluoride caused the differences. It is a reason for follow-up research, and I will treat it that way until stronger data exists.
Thyroid and the wider endocrine system
Evidence: mixed observational data, mostly at exposures above US fluoridation levels.
Fluoride and iodine are chemically related, and at higher exposures fluoride can interfere with iodine handling in the thyroid. The National Research Council's 2006 review identified the endocrine system as sensitive to fluoride and called for more research.5 A 2015 study by Peckham and colleagues compared medical practices across England and found higher rates of recorded hypothyroidism in areas with water fluoride above 0.7 mg/L than in areas below 0.3 mg/L.6 That study was ecological, meaning it compared regions rather than individuals, and it could not account for iodine status or other confounders. Other observational work has found no thyroid effect at fluoridation levels. People with low iodine intake appear most susceptible in the studies that do show an effect, which makes adequate iodine a sensible focus regardless of where you land on fluoride.
Reports linking fluoride to changes in sex hormones, insulin, and cortisol come largely from animal studies and high-exposure populations. I mention them for completeness, not as established effects at 0.7 mg/L.
Reducing fluoride exposure
Evidence: practical guidance based on filtration performance data.
Fluoride's dental benefit works primarily on contact with the tooth surface. Brushing with fluoride toothpaste and spitting it out captures that benefit without the swallowed dose, which is why exposure reduction focuses on drinking water and ingestion. If you want to lower your intake, these are the methods that work.
Filtration that removes fluoride
- Reverse osmosis: forces water through a semi-permeable membrane and removes most fluoride along with a wide range of other contaminants. The most common choice for under-sink installation.
- Activated alumina: a filter medium designed specifically for fluoride, found in some countertop and under-sink systems. Cartridges need replacement on schedule to keep working.
- Distillation: boils water to steam and condenses it, leaving fluoride and other dissolved solids behind. Effective but slow, and it uses more energy than filtration.
Standard carbon pitcher filters do not remove fluoride. If a filter does not name fluoride in its performance data sheet, assume it passes through.
Choosing a filter?
I compared the systems that remove fluoride, aluminum, and PFAS, with a pick for each budget and the performance data behind each one.
Read the Filter GuideBeyond the tap
Many bottled waters contain little or no fluoride, but content varies by brand, so check the water quality report rather than the label alone. Glass bottling also avoids plastic-associated compounds. My personal pick is Mountain Valley spring water, which is bottled in glass and publishes its mineral analysis. Processed drinks and packaged foods made with municipal water carry whatever fluoride that water contained, so cooking at home with filtered water lowers intake further. For children under six, the toothpaste label's pea-sized amount and supervised spitting keep swallowed fluoride low while preserving the dental benefit.
Where the case stands now
Evidence: federal court record, primary documents.
The case has returned to the district court for further proceedings under the Ninth Circuit's instructions.3 The trial court's factual findings about risk at 0.7 mg/L were vacated along with its order, so as of this writing no federal ruling requires the EPA to change fluoridation practice. The underlying scientific question is open in both directions: the appeals court neither endorsed nor rejected the NTP findings. I will update this page as the district court acts on remand.
- Food & Water Watch v. EPA, No. 3:17-cv-02162, N.D. Cal., Sept. 24, 2024 (memorandum decision). ↩
- National Toxicology Program. Monograph on the State of the Science Concerning Fluoride Exposure and Neurodevelopment and Cognition. 2024. ↩
- Food & Water Watch v. EPA, No. 25-384, 9th Cir., May 21, 2026 (memorandum disposition). ↩
- Malin AJ, et al. Fluoride exposure and sleep patterns among older adolescents in the United States. Environmental Health. 2019;18:106. ↩
- National Research Council. Fluoride in Drinking Water: A Scientific Review of EPA's Standards. 2006. ↩
- Peckham S, Lowery D, Spencer S. Are fluoride levels in drinking water associated with hypothyroidism prevalence in England? Journal of Epidemiology and Community Health. 2015;69(7):619-624. ↩
