Fluoride
Metropolitan District Commission
Fluoride occurs naturally in surface and groundwater and is also added to drinking water by many water systems to prevent cavities and support oral health in people.
In 2015, the Department of Health and Human Services updated its recommendation of an optimal level of 0.7 parts per million, or ppm, added to drinking water based on the health benefits of tooth decay prevention. Studies have shown that fluoride added to community water systems at this level reduces dental cavities, especially in children.
And studies have conclusively shown that fluoride in toothpaste and mouthwash can also provide these benefits.
Read More.
Health Concerns
Although the HHS-recommended level of 0.7 ppm can help promote oral health in children and adults, this level is likely too high for bottle-fed babies. EWG recommends that caregivers mix baby formula with fluoride-free water.
And fluoride in water at higher levels can be detrimental for everyone, especially children.
Long-term ingestion of higher levels of fluoride in water increases dental fluorosis, which includes mottling, pitting and weakening of the teeth in children.
A 2024 authoritative assessment by the National Toxicology Program found that higher levels of fluoride exposure, such as drinking water containing more than 1.5 ppm of fluoride, are associated with lower IQ in children. The conclusion was based on studies in human populations outside of the U.S.
Affecting systems with naturally occurring fluoride, EPA’s maximum legal limit is set at 4 parts per million (ppm) to prevent skeletal fluorosis, a condition where bones become brittle and more susceptible to fracture. But these effects may occur at lower levels of exposure, raising concerns that the current limit may not adequately protect public health.
Samples
Samples exceeding legal limit (MCL)
Samples exceeding
health guidelines
Testing results - average by year
| Year | Average result | Samples taken | Detections | Range of results |
|---|---|---|---|---|
| 2018 | 0.331 ppm | 7 | 7 | 0.0300 ppm - 0.740 ppm |
| 2019 | 0.307 ppm | 7 | 3 | ND - 0.740 ppm |
| 2020 | 0.311 ppm | 7 | 3 | ND - 0.730 ppm |
| 2021 | 0.294 ppm | 7 | 3 | ND - 0.700 ppm |
| 2022 | 0.311 ppm | 7 | 3 | ND - 0.750 ppm |
| 2023 | 0.287 ppm | 7 | 3 | ND - 0.680 ppm |
ppm = parts per million
State, National, and Health Guidelines for Drinking Water
EPA Maximum Contaminant
Level (MCL): 4 ppm
ppm = parts per million
All test results
| Date | Lab ID | Result |
|---|---|---|
| 2018-07-18 | AE01630GE | 0.690 ppm |
| 2018-07-18 | AE01632GE | 0.740 ppm |
| 2018-07-18 | AE01640GE | 0.0300 ppm |
| 2018-07-18 | AE01641GE | 0.0400 ppm |
| 2018-07-18 | AE01637GE | 0.0600 ppm |
| 2018-07-18 | AE01636GE | 0.0400 ppm |
| 2018-07-18 | AE01631GE | 0.720 ppm |
| 2019-12-03 | CE70734 | ND |
| 2019-12-03 | CE70735 | ND |
| 2019-12-03 | CE70736 | ND |
| 2019-12-03 | CE70733 | ND |
| 2019-12-03 | CE70741 | 0.680 ppm |
| 2019-12-03 | CE70739 | 0.730 ppm |
| 2019-12-03 | CE70740 | 0.740 ppm |
| 2020-12-08 | IOC1 200600637 | 0.730 ppm |
| 2020-12-08 | IOC1 200600611 | 0.720 ppm |
| 2020-12-08 | IOCR 200600614 | ND |
| 2020-12-08 | IOCR 200600615 | ND |
| 2020-12-08 | IOCR 200600616 | ND |
| 2020-12-08 | IOCR 200600617 | ND |
| 2020-12-09 | IOC1 200600603 | 0.730 ppm |
| 2021-11-23 | E300107450 300107452 | 0.680 ppm |
| 2021-11-23 | I300107476 300107477 | ND |
| 2021-11-23 | E300107451 300107458 | 0.680 ppm |
| 2021-11-29 | E300109635 300109638 | 0.700 ppm |
| 2021-11-29 | I300109610 300109611 | ND |
| 2021-11-30 | I300109649 300109651 | ND |
| 2021-11-30 | I300109650 300109657 | ND |
| 2022-12-08 | I300283837 300283840 | ND |
| 2022-12-08 | 300283822 300283825B | ND |
| 2022-12-15 | E300287100 300287102 | 0.710 ppm |
| 2022-12-15 | I300287081 300287084 | ND |
| 2022-12-15 | I300287109 300287110 | ND |
| 2022-12-15 | E300287072 300287074 | 0.750 ppm |
| 2022-12-15 | E300287053 300287055 | 0.720 ppm |
| 2023-12-05 | E300456248 300456249 | 0.680 ppm |
| 2023-12-05 | I300456268 300456269 | ND |
| 2023-12-05 | I300456261 300456262 | ND |
| 2023-12-05 | I300456281 300456282 | ND |
| 2023-12-06 | E300456222 300456223 | 0.669 ppm |
| 2023-12-06 | E300456228 300456229 | 0.662 ppm |
| 2023-12-06 | I300456234 300456235 | ND |