Fluoride
California Water Service Company - Westlake
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.
Samples
Samples exceeding legal limit (MCL)
Samples exceeding
health guidelines
Testing results - average by year
| Year | Average result | Samples taken | Detections | Range of results |
|---|---|---|---|---|
| 2014 | 0.796 ppm | 23 | 23 | 0.732 ppm - 0.883 ppm |
| 2015 | 0.776 ppm | 24 | 24 | 0.712 ppm - 0.857 ppm |
| 2016 | 0.692 ppm | 24 | 24 | 0.646 ppm - 0.795 ppm |
| 2017 | 0.690 ppm | 24 | 24 | 0.613 ppm - 0.772 ppm |
| 2018 | 0.688 ppm | 24 | 24 | 0.613 ppm - 0.847 ppm |
| 2019 | 0.704 ppm | 24 | 24 | 0.612 ppm - 0.824 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 |
|---|---|---|
| 2014-01-13 | 5701-002-1002 | 0.809 ppm |
| 2014-01-13 | 5701-003-1020 | 0.809 ppm |
| 2014-01-13 | 5701-005-1038 | 0.775 ppm |
| 2014-02-10 | 5701-004-1029 | 0.781 ppm |
| 2014-03-10 | 5701-002-0936 | 0.773 ppm |
| 2014-03-10 | 5701-003-0954 | 0.825 ppm |
| 2014-03-10 | 5701-005-1011 | 0.773 ppm |
| 2014-05-12 | 5701-002-0951 | 0.799 ppm |
| 2014-05-12 | 5701-003-1009 | 0.831 ppm |
| 2014-05-12 | 5701-005-1027 | 0.789 ppm |
| 2014-06-09 | 5701-004-1016 | 0.818 ppm |
| 2014-07-14 | 5701-002-0950 | 0.805 ppm |
| 2014-07-14 | 5701-003-1018 | 0.808 ppm |
| 2014-07-14 | 5701-005-1036 | 0.801 ppm |
| 2014-08-11 | 5701-004-1114 | 0.883 ppm |
| 2014-09-08 | 5701-002-0955 | 0.792 ppm |
| 2014-09-08 | 5701-003-1013 | 0.792 ppm |
| 2014-09-08 | 5701-005-1031 | 0.792 ppm |
| 2014-10-13 | 5701-004-1016 | 0.781 ppm |
| 2014-11-12 | 5701-002-1019 | 0.735 ppm |
| 2014-11-12 | 5701-003-1037 | 0.772 ppm |
| 2014-11-12 | 5701-005-1055 | 0.732 ppm |
| 2014-12-08 | 5701-004-1133 | 0.833 ppm |
| 2015-01-12 | 5701-002-0909 | 0.790 ppm |
| 2015-01-12 | 5701-003-0927 | 0.834 ppm |
| 2015-01-12 | 5701-005-1331 | 0.785 ppm |
| 2015-02-09 | 5701-004-1052 | 0.843 ppm |
| 2015-03-09 | 5701-002-1020 | 0.784 ppm |
| 2015-03-09 | 5701-003-1038 | 0.777 ppm |
| 2015-03-09 | 5701-005-1056 | 0.778 ppm |
| 2015-04-13 | 5701-004-1044 | 0.822 ppm |
| 2015-05-11 | 5701-002-1020 | 0.850 ppm |
| 2015-05-11 | 5701-003-1038 | 0.857 ppm |
| 2015-05-11 | 5701-005-1056 | 0.799 ppm |
| 2015-06-08 | 5701-004-1124 | 0.796 ppm |
| 2015-07-13 | 5701-002-1005 | 0.746 ppm |
| 2015-07-13 | 5701-003-1023 | 0.774 ppm |
| 2015-07-13 | 5701-005-1041 | 0.742 ppm |
| 2015-08-10 | 5701-004-1053 | 0.712 ppm |
| 2015-09-14 | 5701-002-1010 | 0.752 ppm |
| 2015-09-14 | 5701-003-1025 | 0.752 ppm |
| 2015-09-14 | 5701-005-1046 | 0.751 ppm |
| 2015-10-13 | 5701-004-1042 | 0.714 ppm |
| 2015-11-09 | 5701-002-0958 | 0.742 ppm |
| 2015-11-09 | 5701-003-1016 | 0.742 ppm |
| 2015-11-09 | 5701-005-1034 | 0.761 ppm |
| 2015-12-14 | 5701-004-1114 | 0.713 ppm |
| 2016-01-11 | 5701-002-1020 | 0.744 ppm |
| 2016-01-11 | 5701-003-1038 | 0.752 ppm |
| 2016-01-11 | 5701-005-1056 | 0.704 ppm |
| 2016-02-16 | 5701-004-1014 | 0.708 ppm |
| 2016-03-14 | 5701-002-0930 | 0.693 ppm |
| 2016-03-14 | 5701-003-0948 | 0.699 ppm |
| 2016-03-14 | 5701-005-1006 | 0.679 ppm |
| 2016-04-11 | 5701-004-1037 | 0.795 ppm |
| 2016-05-09 | 5701-002-1018 | 0.683 ppm |
| 2016-05-09 | 5701-003-1036 | 0.730 ppm |
| 2016-05-09 | 5701-005-1054 | 0.682 ppm |
| 2016-06-13 | 5701-004-1015 | 0.654 ppm |
| 2016-07-05 | 5701-002-0912 | 0.646 ppm |
| 2016-07-05 | 5701-003-0929 | 0.691 ppm |
| 2016-07-05 | 5701-005-0947 | 0.646 ppm |
| 2016-08-08 | 5701-004-1042 | 0.705 ppm |
| 2016-09-12 | 5701-002-0938 | 0.699 ppm |
| 2016-09-12 | 5701-003-1124 | 0.702 ppm |
| 2016-09-12 | 5701-005-1142 | 0.665 ppm |
| 2016-10-12 | 5701-004-1052 | 0.650 ppm |
| 2016-11-14 | 5701-002-0958 | 0.654 ppm |
| 2016-11-14 | 5701-003-1016 | 0.699 ppm |
| 2016-11-14 | 5701-005-1034 | 0.653 ppm |
| 2016-12-12 | 5701-004-1102 | 0.671 ppm |
| 2017-01-17 | 5701-002-0958 | 0.674 ppm |
| 2017-01-17 | 5701-003-1016 | 0.744 ppm |
| 2017-01-17 | 5701-005-1034 | 0.682 ppm |
| 2017-02-07 | 5701-004-1042 | 0.702 ppm |
| 2017-03-13 | 5701-002-1008 | 0.673 ppm |
| 2017-03-13 | 5701-003-1026 | 0.688 ppm |
| 2017-03-13 | 5701-005-1044 | 0.613 ppm |
| 2017-04-10 | 5701-004-1042 | 0.659 ppm |
| 2017-05-10 | 5701-002-1004 | 0.639 ppm |
| 2017-05-10 | 5701-003-1022 | 0.649 ppm |
| 2017-05-10 | 5701-005-1040 | 0.649 ppm |
| 2017-06-12 | 5701-004-1054 | 0.641 ppm |
| 2017-07-10 | 5701-002-0948 | 0.629 ppm |
| 2017-07-10 | 5701-003-1006 | 0.705 ppm |
| 2017-07-10 | 5701-005-1024 | 0.634 ppm |
| 2017-08-14 | 5701-004-1042 | 0.685 ppm |
| 2017-09-11 | 5701-002-0910 | 0.730 ppm |
| 2017-09-11 | 5701-003-0946 | 0.712 ppm |
| 2017-09-11 | 5701-005-0928 | 0.732 ppm |
| 2017-10-11 | 5701-004-1114 | 0.756 ppm |
| 2017-11-13 | 5701-002-1000 | 0.765 ppm |
| 2017-11-13 | 5701-003-1018 | 0.758 ppm |
| 2017-11-13 | 5701-005-1036 | 0.772 ppm |
| 2017-12-11 | 5701-004-1112 | 0.667 ppm |
| 2018-01-08 | 5701-002-0938 | 0.657 ppm |
| 2018-01-08 | 5701-003-0956 | 0.630 ppm |
| 2018-01-08 | 5701-005-1014 | 0.638 ppm |
| 2018-02-12 | 5701-004-1042 | 0.623 ppm |
| 2018-03-12 | 5701-002-0910 | 0.847 ppm |
| 2018-03-12 | 5701-003-0928 | 0.818 ppm |
| 2018-03-12 | 5701-005-0946 | 0.840 ppm |
| 2018-04-09 | 5701-004-1056 | 0.645 ppm |
| 2018-05-14 | 5701-002-0954 | 0.677 ppm |
| 2018-05-14 | 5701-003-1012 | 0.685 ppm |
| 2018-05-14 | 5701-005-1030 | 0.613 ppm |
| 2018-06-11 | 5701-004-0942 | 0.699 ppm |
| 2018-07-09 | 5701-002-1004 | 0.659 ppm |
| 2018-07-09 | 5701-003-1022 | 0.664 ppm |
| 2018-07-09 | 5701-005-1040 | 0.658 ppm |
| 2018-08-13 | 5701-004-1118 | 0.628 ppm |
| 2018-09-10 | 5701-002-0956 | 0.695 ppm |
| 2018-09-10 | 5701-003-0956 | 0.698 ppm |
| 2018-09-10 | 5701-005-0956 | 0.708 ppm |
| 2018-10-08 | 5701-004-1050 | 0.639 ppm |
| 2018-11-13 | 5701-002-0952 | 0.708 ppm |
| 2018-11-13 | 5701-003-1016 | 0.701 ppm |
| 2018-11-13 | 5701-005-1034 | 0.709 ppm |
| 2018-12-10 | 5701-004-1058 | 0.668 ppm |
| 2019-01-15 | 5701-002-0916 | 0.804 ppm |
| 2019-01-15 | 5701-003-0934 | 0.799 ppm |
| 2019-01-15 | 5701-005-0952 | 0.824 ppm |
| 2019-02-11 | 5701-004-0943 | 0.810 ppm |
| 2019-03-11 | 5701-002-1004 | 0.766 ppm |
| 2019-03-11 | 5701-003-1022 | 0.775 ppm |
| 2019-03-11 | 5701-005-1040 | 0.760 ppm |
| 2019-04-08 | 5810-004-1046 | 0.790 ppm |
| 2019-05-06 | 5701-002-1059 | 0.687 ppm |
| 2019-05-06 | 5701-003-1117 | 0.687 ppm |
| 2019-05-06 | 5701-005-1135 | 0.690 ppm |
| 2019-06-10 | 5701-004-1044 | 0.702 ppm |
| 2019-07-08 | 5701-002-1002 | 0.671 ppm |
| 2019-07-08 | 5701-003-1020 | 0.671 ppm |
| 2019-07-08 | 5701-005-1038 | 0.673 ppm |
| 2019-08-12 | 5701-004-0930 | 0.690 ppm |
| 2019-09-09 | 5701-002-1235 | 0.641 ppm |
| 2019-09-09 | 5701-003-1220 | 0.641 ppm |
| 2019-09-09 | 5701-005-1202 | 0.639 ppm |
| 2019-10-14 | 5701-004-0946 | 0.612 ppm |
| 2019-11-12 | 5701-002-1230 | 0.621 ppm |
| 2019-11-12 | 5701-003-1214 | 0.619 ppm |
| 2019-11-12 | 5701-005-1158 | 0.619 ppm |
| 2019-12-09 | 5701-004-1014 | 0.696 ppm |