Fluoride
City of Houston
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 |
---|---|---|---|---|
2013 | N/A | 0 | 0 | N/A |
2014 | 0.265 ppm | 35 | 34 | ND - 0.430 ppm |
2015 | 0.254 ppm | 12 | 11 | ND - 0.360 ppm |
2016 | 0.326 ppm | 18 | 17 | ND - 0.760 ppm |
2017 | 0.306 ppm | 33 | 32 | ND - 0.510 ppm |
2018 | 0.315 ppm | 12 | 12 | 0.110 ppm - 0.580 ppm |
2019 | 0.272 ppm | 18 | 17 | ND - 0.740 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 |
---|---|---|
2014-02-03 | AC40994 | 0.290 ppm |
2014-03-14 | AC47039 | 0.240 ppm |
2014-03-14 | AC47038 | 0.260 ppm |
2014-03-14 | AC47037 | 0.250 ppm |
2014-04-16 | AC50723 | 0.270 ppm |
2014-04-16 | AC50724 | 0.280 ppm |
2014-04-16 | AC50734 | 0.290 ppm |
2014-04-17 | AC50993 | 0.240 ppm |
2014-04-17 | AC50990 | 0.280 ppm |
2014-04-17 | AC50991 | 0.190 ppm |
2014-04-17 | AC50994 | 0.190 ppm |
2014-04-17 | AC50992 | 0.310 ppm |
2014-04-17 | AC50995 | 0.310 ppm |
2014-04-17 | AC50996 | 0.190 ppm |
2014-04-17 | AC50997 | 0.200 ppm |
2014-06-03 | AC55755 | 0.410 ppm |
2014-06-03 | AC55754 | 0.230 ppm |
2014-06-03 | AC55753 | 0.160 ppm |
2014-06-03 | AC55750 | 0.430 ppm |
2014-06-03 | AC55757 | ND |
2014-07-15 | AC59659 | 0.340 ppm |
2014-07-15 | AC59660 | 0.320 ppm |
2014-07-16 | AC59795 | 0.330 ppm |
2014-08-14 | AC63605 | 0.400 ppm |
2014-10-08 | AC69105 | 0.210 ppm |
2014-10-08 | AC69106 | 0.220 ppm |
2014-10-08 | AC69107 | 0.270 ppm |
2014-10-09 | AC69313 | 0.350 ppm |
2014-10-09 | AC69315 | 0.200 ppm |
2014-10-09 | AC69316 | 0.200 ppm |
2014-12-09 | AC74116 | 0.260 ppm |
2014-12-09 | AC74115 | 0.250 ppm |
2014-12-09 | AC74114 | 0.260 ppm |
2014-12-18 | AC75400 | 0.340 ppm |
2014-12-18 | AC75401 | 0.310 ppm |
2015-03-04 | AC82786 | 0.310 ppm |
2015-03-05 | AC82798 | 0.310 ppm |
2015-06-04 | AC94552 | 0.260 ppm |
2015-06-04 | AC94555 | ND |
2015-06-04 | AC94553 | 0.180 ppm |
2015-06-04 | AC94554 | 0.340 ppm |
2015-07-21 | AD00295 | 0.230 ppm |
2015-07-21 | AD00297 | 0.360 ppm |
2015-07-21 | AD00294 | 0.290 ppm |
2015-07-21 | AD00296 | 0.230 ppm |
2015-09-17 | AD07488 | 0.260 ppm |
2015-11-12 | AD13292 | 0.280 ppm |
2016-02-18 | AD24162 | 0.350 ppm |
2016-03-03 | AD26801 | 0.180 ppm |
2016-03-16 | AD28948 | 0.190 ppm |
2016-03-16 | AD28947 | 0.190 ppm |
2016-03-17 | AD29277 | 0.520 ppm |
2016-03-17 | AD29276 | 0.230 ppm |
2016-03-23 | AD30035 | 0.210 ppm |
2016-03-23 | AD30037 | 0.310 ppm |
2016-03-23 | AD30034 | ND |
2016-09-20 | AD50262 | 0.350 ppm |
2016-09-20 | AD50263 | 0.530 ppm |
2016-09-21 | AD50627 | 0.430 ppm |
2016-10-06 | AD52612 | 0.260 ppm |
2016-10-06 | AD52609 | 0.430 ppm |
2016-10-06 | AD52610 | 0.260 ppm |
2016-10-06 | AD52611 | 0.200 ppm |
2016-10-06 | AD52613 | 0.470 ppm |
2016-11-21 | AD58715 | 0.760 ppm |
2017-01-26 | AD66988 | 0.220 ppm |
2017-01-26 | AD66986 | 0.220 ppm |
2017-01-26 | AD66985 | 0.410 ppm |
2017-02-28 | AD72314 | 0.480 ppm |
2017-02-28 | AD72319 | 0.280 ppm |
2017-03-01 | AD72660 | 0.450 ppm |
2017-03-01 | AD72659 | 0.440 ppm |
2017-03-02 | AD72953 | 0.460 ppm |
2017-03-02 | AD72952 | ND |
2017-03-28 | AD77033 | 0.200 ppm |
2017-03-28 | AD77034 | 0.230 ppm |
2017-03-28 | AD77036 | 0.200 ppm |
2017-03-28 | AD77035 | 0.460 ppm |
2017-03-29 | AD77322 | 0.410 ppm |
2017-03-29 | AD77336 | 0.460 ppm |
2017-04-26 | AD81069 | 0.500 ppm |
2017-04-27 | AD81369 | 0.220 ppm |
2017-07-06 | AD88401 | 0.340 ppm |
2017-07-06 | AD88402 | 0.230 ppm |
2017-07-06 | AD88403 | 0.170 ppm |
2017-07-25 | AD90455 | 0.380 ppm |
2017-09-11 | AD95335 | 0.270 ppm |
2017-09-11 | AD95337 | 0.410 ppm |
2017-09-11 | AD95336 | 0.220 ppm |
2017-09-26 | AD97896 | 0.510 ppm |
2017-09-26 | AD97894 | 0.230 ppm |
2017-09-26 | AD97893 | 0.200 ppm |
2017-09-26 | AD97895 | 0.210 ppm |
2017-11-07 | AE03760 | 0.310 ppm |
2017-11-07 | AE03762 | 0.260 ppm |
2017-11-07 | AE03761 | 0.280 ppm |
2017-11-07 | AE03764 | 0.200 ppm |
2017-11-07 | AE03763 | 0.230 ppm |
2018-01-18 | AE09171 | 0.450 ppm |
2018-01-18 | AE09172 | 0.380 ppm |
2018-01-18 | AE09173 | 0.210 ppm |
2018-01-23 | AE09766 | 0.270 ppm |
2018-01-23 | AE09768 | 0.210 ppm |
2018-01-23 | AE09767 | 0.340 ppm |
2018-01-31 | AE11428 | 0.110 ppm |
2018-08-03 | AE35739 | 0.260 ppm |
2018-08-15 | AE37093 | 0.240 ppm |
2018-08-15 | AE37096 | 0.480 ppm |
2018-08-15 | AE37098 | 0.580 ppm |
2018-09-26 | AE41665 | 0.250 ppm |
2019-01-15 | AE50001 | 0.150 ppm |
2019-01-15 | AE50000 | 0.150 ppm |
2019-01-16 | AE49999 | 0.270 ppm |
2019-03-06 | AE57303 | 0.210 ppm |
2019-03-06 | AE57302 | 0.280 ppm |
2019-03-06 | AE57301 | 0.490 ppm |
2019-03-06 | AE57299 | ND |
2019-04-10 | AE61953 | 0.390 ppm |
2019-04-11 | AE61954 | 0.560 ppm |
2019-06-25 | AE71876 | 0.340 ppm |
2019-06-25 | AE71877 | 0.300 ppm |
2019-07-25 | AE75868 | 0.180 ppm |
2019-07-25 | AE75869 | 0.180 ppm |
2019-09-23 | AE84164 | 0.110 ppm |
2019-09-23 | AE84163 | 0.120 ppm |
2019-11-18 | AE89429 | 0.230 ppm |
2019-12-02 | AE90768 | 0.740 ppm |
2019-12-02 | AE90767 | 0.190 ppm |