Fluoride
Cal/Am Water Company - San Marino
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 | 0.839 ppm | 12 | 12 | 0.640 ppm - 1.05 ppm |
2015 | 0.799 ppm | 12 | 12 | 0.580 ppm - 1.06 ppm |
2016 | 0.773 ppm | 24 | 24 | 0.460 ppm - 1.08 ppm |
2017 | 0.830 ppm | 1 | 1 | 0.830 ppm |
2018 | 0.780 ppm | 1 | 1 | 0.780 ppm |
2019 | 0.785 ppm | 22 | 22 | 0.580 ppm - 1.000 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 |
---|---|---|
2014-01-29 | 9590-007-1000 | 0.650 ppm |
2014-04-14 | 1225-006-1050 | 0.650 ppm |
2014-04-14 | 1225-044-0925 | 0.740 ppm |
2014-04-14 | 1225-032-1015 | 0.880 ppm |
2014-04-14 | 1225-029-0950 | 1.05 ppm |
2014-04-14 | 1225-023-0935 | 0.940 ppm |
2014-04-14 | 1225-020-1045 | 0.880 ppm |
2014-04-14 | 1225-007-1110 | 0.640 ppm |
2014-04-14 | 1225-011-0855 | 0.870 ppm |
2014-05-12 | 1225-014-1300 | 0.980 ppm |
2014-05-19 | 1225-010-0850 | 0.880 ppm |
2014-06-23 | 1225-017-1045 | 0.910 ppm |
2015-05-12 | 1225-017-1245 | 0.890 ppm |
2015-05-12 | 1225-007-1200 | 0.580 ppm |
2015-05-18 | 1225-032-1130 | 0.850 ppm |
2015-05-18 | 1225-044-1110 | 1.06 ppm |
2015-05-18 | 1225-011-1050 | 0.810 ppm |
2015-05-18 | 1225-023-1110 | 0.920 ppm |
2015-05-20 | 1225-029-1235 | 0.790 ppm |
2015-05-20 | 1225-006-1255 | 0.660 ppm |
2015-05-27 | 1225-010-0830 | 0.820 ppm |
2015-05-27 | 1225-020-0855 | 0.820 ppm |
2015-09-08 | 9588-010-0915 | 0.690 ppm |
2015-09-08 | 9588-020-0935 | 0.700 ppm |
2016-06-06 | 1225-032-1105 | 1.08 ppm |
2016-06-06 | 1225-044-1000 | 0.770 ppm |
2016-06-06 | 1225-029-1045 | 0.960 ppm |
2016-06-06 | 1225-023-1135 | 0.920 ppm |
2016-06-06 | 1225-006-1100 | 0.650 ppm |
2016-06-06 | 1225-020-1040 | 0.910 ppm |
2016-06-06 | 1225-007-1210 | 0.600 ppm |
2016-06-06 | 1225-010-1000 | 0.850 ppm |
2016-06-06 | 1225-017-1130 | 0.940 ppm |
2016-06-09 | 9588-007-0915 | 0.460 ppm |
2016-09-07 | 9588-011-1105 | 0.590 ppm |
2016-09-07 | 9588-017-1020 | 0.720 ppm |
2016-09-07 | 9588-023-1120 | 0.710 ppm |
2016-09-07 | 9588-032-1140 | 0.860 ppm |
2016-09-14 | 9590-006-0930 | 0.590 ppm |
2016-09-14 | 9590-007-0835 | 0.530 ppm |
2016-09-14 | 9590-010-0805 | 0.780 ppm |
2016-09-14 | 9590-044-0945 | 0.660 ppm |
2016-09-14 | 9590-032-1225 | 1.000 ppm |
2016-09-14 | 9590-011-1130 | 0.710 ppm |
2016-09-14 | 9590-029-0920 | 0.740 ppm |
2016-09-14 | 9590-020-1145 | 0.830 ppm |
2016-09-14 | 9590-017-0900 | 0.860 ppm |
2016-09-14 | 9590-023-1200 | 0.830 ppm |
2017-01-17 | 9590-020-1010 | 0.830 ppm |
2018-09-20 | 9588-020-1040 | 0.780 ppm |
2019-05-13 | 9588-017-1015 | 1.000 ppm |
2019-05-13 | 9588-020-0930 | 0.890 ppm |
2019-05-13 | 9588-032-0955 | 0.900 ppm |
2019-05-13 | 9588-023-0945 | 0.970 ppm |
2019-05-15 | 9590-006-1130 | 0.590 ppm |
2019-05-15 | 9590-044-0925 | 0.670 ppm |
2019-05-15 | 9590-029-0845 | 0.890 ppm |
2019-06-18 | 9588-011-1005 | 0.780 ppm |
2019-06-18 | 9588-007-1050 | 0.660 ppm |
2019-06-18 | 9590-007-1155 | 0.620 ppm |
2019-07-10 | 9590-017-1041 | 0.950 ppm |
2019-07-10 | 9590-006-1009 | 0.620 ppm |
2019-07-10 | 9590-011-0939 | 0.670 ppm |
2019-07-10 | 9590-007-1104 | 0.580 ppm |
2019-07-10 | 9590-044-1020 | 0.670 ppm |
2019-07-10 | 9590-020-0921 | 0.820 ppm |
2019-07-10 | 9590-032-0823 | 0.830 ppm |
2019-07-10 | 9590-023-0833 | 0.870 ppm |
2019-07-10 | 9590-029-1032 | 0.930 ppm |
2019-07-17 | 9590-011-1050 | 0.690 ppm |
2019-08-26 | 9588-010-0945 | 0.800 ppm |
2019-08-26 | 9590-010-1001 | 0.870 ppm |