Know Your Environment. Protect Your Health.

Fluoride

Manchester Water Department

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.

 

30

Samples

0

Samples exceeding legal limit (MCL)

0

Samples exceeding
health guidelines

Testing results - average by year

 
YearAverage resultSamples takenDetectionsRange of results
20180.604 ppm87ND - 0.780 ppm
20190.415 ppm21ND - 0.830 ppm
20200.626 ppm87ND - 0.800 ppm
20210.345 ppm21ND - 0.690 ppm
20220.369 ppm21ND - 0.737 ppm
20230.625 ppm87ND - 0.860 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
2018-02-05AA82672-IOC10.660 ppm
2018-02-05AA82673-IOC10.780 ppm
2018-02-05AA82666-IOC10.730 ppm
2018-02-06AA82689-IOC10.530 ppm
2018-02-06AA82690-IOC10.750 ppm
2018-02-07AA82711-IOC10.760 ppm
2018-02-07AA82712-IOC10.620 ppm
2018-02-23AA82899-IOCRND
2019-05-03AA88242-IOC10.830 ppm
2019-05-16AA88408-IOCRND
2020-10-01AA94988-IOCRND
2020-12-07AA95917-IOC10.690 ppm
2020-12-07AA95918-IOC10.640 ppm
2020-12-08AA95934-IOC10.800 ppm
2020-12-08AA95935-IOC10.750 ppm
2020-12-09AA95952-IOC10.720 ppm
2020-12-09AA95953-IOC10.710 ppm
2020-12-10AA95963-IOC10.700 ppm
2021-11-04211104-1-06IOC0.690 ppm
2021-11-04211104-1-04RAW IOCND
2022-05-13220513-1-04 RAW IOCND
2022-06-03220603-1-06IOC0.737 ppm
2023-12-04231204-3-01IOC0.710 ppm
2023-12-04231204-3-02 IOC0.570 ppm
2023-12-05231205-1-06 IOC0.651 ppm
2023-12-05231205-3-03 IOC0.750 ppm
2023-12-05231205-3-04 IOC0.720 ppm
2023-12-05231205-1-04 RAW IOCND
2023-12-06231206-3-05 IOC0.740 ppm
2023-12-06231206-3-06 IOC0.860 ppm