Fluoride
Bi County WSC 1
Fluoride occurs naturally in surface and groundwater and is also added to drinking water by many water systems. Read More.
Fluoride has been promoted as a chemical that reduces dental cavities. Yet it is now well-established that fluoride primarily exerts its protective effects through topical mechanisms, such as sodium fluoride in toothpaste and mouthwash. In contrast, long-term ingestion of fluoride in water increases dental fluorosis, which includes mottling, pitting and weakening of the teeth. 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 fractures, although these effects may occur at lower doses.
Even fluoride levels of 0.7 ppm, the amount of fluoride in drinking water recommended by the U.S. Public Health Service, can result in too much fluoride for bottle-fed babies. EWG recommends that caregivers mix baby formula with fluoride-free water. The National Toxicology Program is investigating the potential for low doses of fluoride to alter thyroid function and childhood brain development.
Testing results - average by year
Year | Average result | Samples taken | Detections | Range of results |
---|---|---|---|---|
2014 | 0.180 ppm | 4 | 4 | 0.153 ppm - 0.198 ppm |
2015 | N/A | 0 | 0 | N/A |
2016 | 0.393 ppm | 7 | 7 | 0.154 ppm - 0.707 ppm |
2017 | 0.164 ppm | 4 | 4 | 0.150 ppm - 0.181 ppm |
2018 | N/A | 0 | 0 | N/A |
2019 | 0.368 ppm | 8 | 8 | 0.164 ppm - 0.560 ppm |
ppm = parts per million
State and national drinking water standards and health guidelines
EPA Maximum Contaminant
Level (MCL) 4 ppm
ppm = parts per million
All test results
Date | Lab ID | Result |
---|---|---|
2014-01-23 | Q1402181045 | 0.184 ppm |
2014-01-23 | Q1402181044 | 0.153 ppm |
2014-01-23 | Q1402181043 | 0.184 ppm |
2014-01-23 | Q1402181042 | 0.198 ppm |
2016-04-19 | Q1615295015 | 0.488 ppm |
2016-04-19 | Q1615295014 | 0.707 ppm |
2016-10-06 | Q1642553023 | 0.215 ppm |
2016-10-06 | Q1642553022 | 0.414 ppm |
2016-10-06 | Q1642553021 | 0.154 ppm |
2016-10-06 | Q1642553020 | 0.342 ppm |
2016-10-06 | Q1642553019 | 0.434 ppm |
2017-01-05 | Q1700559007 | 0.154 ppm |
2017-01-05 | Q1700559029 | 0.150 ppm |
2017-01-05 | Q1700559006 | 0.181 ppm |
2017-03-29 | Q1713282013 | 0.172 ppm |
2019-01-15 | Q1902083029 | 0.240 ppm |
2019-01-15 | Q1902083028 | 0.382 ppm |
2019-01-15 | Q1902083027 | 0.560 ppm |
2019-01-15 | Q1902083026 | 0.164 ppm |
2019-01-29 | Q1904181002 | 0.461 ppm |
2019-01-29 | Q1904181001 | 0.376 ppm |
2019-01-29 | Q1904181009 | 0.499 ppm |
2019-06-11 | Q1934121008 | 0.258 ppm |