Fluoride
Connecticut Water Company - Northern Reg-reservoir Heights
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 | 0.651 ppm | 12 | 12 | 0.530 ppm - 0.700 ppm |
| 2019 | 0.701 ppm | 12 | 12 | 0.640 ppm - 0.740 ppm |
| 2020 | 0.694 ppm | 12 | 12 | 0.620 ppm - 0.810 ppm |
| 2021 | 0.703 ppm | 11 | 11 | 0.610 ppm - 0.750 ppm |
| 2022 | 0.458 ppm | 12 | 12 | 0.270 ppm - 0.560 ppm |
| 2023 | 0.492 ppm | 12 | 12 | 0.390 ppm - 0.570 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 |
|---|---|---|
| 2018-01-10 | BZ71225IOC1 | 0.530 ppm |
| 2018-02-08 | BZ86705IOC1 | 0.600 ppm |
| 2018-03-20 | CA06187IOC1 | 0.700 ppm |
| 2018-04-11 | CA18547IOC1 | 0.580 ppm |
| 2018-05-02 | CA40226IOC1 | 0.690 ppm |
| 2018-06-12 | CA69433IOC1 | 0.660 ppm |
| 2018-07-16 | CA91169 | 0.680 ppm |
| 2018-08-08 | CB07752 | 0.660 ppm |
| 2018-09-25 | IOC 200506739 | 0.680 ppm |
| 2018-10-22 | IOC 200509965 | 0.680 ppm |
| 2018-11-12 | IOC 200512389 | 0.690 ppm |
| 2018-12-05 | IOC 200515005 | 0.660 ppm |
| 2019-01-23 | IOC 200519511 | 0.640 ppm |
| 2019-02-05 | IOC1 200520603 | 0.680 ppm |
| 2019-03-13 | IOC1 200524661 | 0.730 ppm |
| 2019-04-10 | IOC1 200527950 | 0.680 ppm |
| 2019-05-21 | IOC1 200533124 | 0.740 ppm |
| 2019-06-18 | IOC 200536921 | 0.660 ppm |
| 2019-07-17 | IOC1 200540984 | 0.670 ppm |
| 2019-08-14 | IOC1 200544962 | 0.710 ppm |
| 2019-09-24 | IOC1 200550207 | 0.730 ppm |
| 2019-10-14 | IOC1 200552679 | 0.710 ppm |
| 2019-11-19 | IOC1 200557290 | 0.720 ppm |
| 2019-12-05 | IOC1 200559167 | 0.740 ppm |
| 2020-01-14 | IOC1 200562911 | 0.670 ppm |
| 2020-02-19 | IOC1 200566771 | 0.740 ppm |
| 2020-03-23 | IOC1 200570229 | 0.710 ppm |
| 2020-04-15 | IOC1 200572541 | 0.730 ppm |
| 2020-05-12 | IOC1 200575436 | 0.700 ppm |
| 2020-06-09 | IOC1 200578588 | 0.620 ppm |
| 2020-07-14 | IOC 200582695 | 0.680 ppm |
| 2020-08-25 | IOC1 200587882 | 0.810 ppm |
| 2020-09-23 | IOC1 200591514 | 0.680 ppm |
| 2020-10-28 | IOCR 200595649 | 0.700 ppm |
| 2020-11-11 | IOC1 200597699 | 0.630 ppm |
| 2020-12-02 | IOC1 200600970 | 0.660 ppm |
| 2021-01-20 | IOC 200604504 | 0.690 ppm |
| 2021-02-09 | IOC1 200606088 | 0.730 ppm |
| 2021-03-10 | IOC 200609378 | 0.610 ppm |
| 2021-04-19 | IOC1 200613668 | 0.730 ppm |
| 2021-05-25 | IOC1 200618490 | 0.740 ppm |
| 2021-06-22 | IOC1 200621876 | 0.710 ppm |
| 2021-08-11 | IOC1 200628245 | 0.750 ppm |
| 2021-09-28 | F300069840 300069842 | 0.680 ppm |
| 2021-10-11 | F300078108 300078109 | 0.690 ppm |
| 2021-11-15 | F300102586 300102588 | 0.730 ppm |
| 2021-12-28 | F300125121 300125123 | 0.670 ppm |
| 2022-01-25 | CK23180 | 0.350 ppm |
| 2022-02-07 | CK31630 | 0.370 ppm |
| 2022-03-16 | CK88555 | 0.520 ppm |
| 2022-04-12 | CL07277 | 0.560 ppm |
| 2022-05-25 | CL38014 | 0.560 ppm |
| 2022-06-13 | CL55471 | 0.380 ppm |
| 2022-07-12 | CL76048 | 0.490 ppm |
| 2022-08-24 | CM14035 | 0.480 ppm |
| 2022-09-27 | CM42446 | 0.270 ppm |
| 2022-10-11 | CM59729 | 0.470 ppm |
| 2022-11-08 | CM80260 | 0.490 ppm |
| 2022-12-14 | CN05220 | 0.550 ppm |
| 2023-01-10 | CN20812 | 0.560 ppm |
| 2023-02-07 | CN38156 | 0.480 ppm |
| 2023-03-08 | CN56099 | 0.560 ppm |
| 2023-04-04 | CN75903 | 0.450 ppm |
| 2023-05-10 | CO03413 | 0.410 ppm |
| 2023-06-12 | CO25905 | 0.500 ppm |
| 2023-07-17 | CO52486 | 0.390 ppm |
| 2023-08-01 | CO63967 | 0.490 ppm |
| 2023-09-12 | CO94971 | 0.570 ppm |
| 2023-10-02 | CP13197 | 0.570 ppm |
| 2023-11-28 | CP54249 | 0.430 ppm |
| 2023-12-20 | CP72604 | 0.490 ppm |