Fluoride
Siloam Springs Waterworks
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 |
|---|---|---|---|---|
| 2013 | N/A | 0 | 0 | N/A |
| 2014 | 0.613 ppm | 12 | 12 | 0.340 ppm - 0.850 ppm |
| 2015 | 0.793 ppm | 13 | 13 | 0.530 ppm - 1.000 ppm |
| 2016 | 0.672 ppm | 11 | 11 | 0.550 ppm - 0.860 ppm |
| 2017 | 0.688 ppm | 12 | 12 | 0.340 ppm - 0.960 ppm |
| 2018 | 0.601 ppm | 13 | 12 | ND - 0.850 ppm |
| 2019 | 0.618 ppm | 13 | 13 | 0.400 ppm - 0.780 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 |
|---|---|---|
| 2014-01-14 | 140160018 | 0.710 ppm |
| 2014-02-11 | 140490018 | 0.470 ppm |
| 2014-03-05 | 140690005 | 0.630 ppm |
| 2014-04-01 | 140970008 | 0.500 ppm |
| 2014-04-23 | 141140005 | 0.820 ppm |
| 2014-05-06 | 141320017 | 0.670 ppm |
| 2014-06-03 | 141600004 | 0.340 ppm |
| 2014-08-05 | 142230018 | 0.670 ppm |
| 2014-09-02 | 142510010 | 0.570 ppm |
| 2014-10-07 | Y142860008 | 0.850 ppm |
| 2014-11-04 | Y143110009 | 0.570 ppm |
| 2014-12-09 | Y143490022 | 0.560 ppm |
| 2015-01-06 | Y150130017 | 0.680 ppm |
| 2015-02-10 | Y150500015 | 0.700 ppm |
| 2015-03-10 | Y150750007 | 0.530 ppm |
| 2015-04-08 | Y150990025 | 0.800 ppm |
| 2015-04-14 | Y151140012 | 0.530 ppm |
| 2015-05-05 | Y151280035 | 1.000 ppm |
| 2015-06-02 | Y151550046 | 0.990 ppm |
| 2015-07-21 | Y152080006 | 1.000 ppm |
| 2015-08-04 | Y152180004 | 0.710 ppm |
| 2015-09-15 | Y152650012 | 0.990 ppm |
| 2015-10-06 | Y152850012 | 0.960 ppm |
| 2015-11-03 | Y153130027 | 0.850 ppm |
| 2015-12-15 | Y153520006 | 0.570 ppm |
| 2016-01-05 | Y160080038 | 0.610 ppm |
| 2016-03-08 | Y160740006 | 0.550 ppm |
| 2016-04-05 | Y161040012 | 0.550 ppm |
| 2016-04-20 | Y161120011 | 0.590 ppm |
| 2016-06-07 | Y161650028 | 0.860 ppm |
| 2016-07-26 | Y162210005 | 0.810 ppm |
| 2016-08-02 | Y162170018 | 0.830 ppm |
| 2016-09-13 | Y162640054 | 0.610 ppm |
| 2016-10-12 | Y162880092 | 0.730 ppm |
| 2016-11-08 | Y163140035 | 0.700 ppm |
| 2016-12-13 | Y163500008 | 0.550 ppm |
| 2017-01-10 | Y170110010 | 0.340 ppm |
| 2017-02-21 | Y170580011 | 0.640 ppm |
| 2017-03-14 | Y170790037 | 0.920 ppm |
| 2017-04-04 | Y171000012 | 0.620 ppm |
| 2017-04-18 | Y171100001 | 0.600 ppm |
| 2017-05-02 | Y171280006 | 0.760 ppm |
| 2017-06-13 | Y171700021 | 0.480 ppm |
| 2017-07-12 | Y171980053 | 0.720 ppm |
| 2017-09-19 | Y172680020 | 0.880 ppm |
| 2017-10-03 | Y172820019 | 0.720 ppm |
| 2017-11-07 | Y173170024 | 0.960 ppm |
| 2017-12-05 | Y173450037 | 0.610 ppm |
| 2018-01-09 | Y180180044 | 0.600 ppm |
| 2018-02-06 | Y180430004 | 0.620 ppm |
| 2018-03-06 | Y180660043 | 0.700 ppm |
| 2018-04-03 | Y180990008 | 0.700 ppm |
| 2018-05-08 | Y181340027 | 0.640 ppm |
| 2018-05-15 | Y181370006 | ND |
| 2018-06-05 | Y181620017 | 0.490 ppm |
| 2018-07-17 | Y182050019 | 0.600 ppm |
| 2018-08-07 | Y182250023 | 0.540 ppm |
| 2018-09-04 | Y182530011 | 0.660 ppm |
| 2018-10-01 | Y182750032 | 0.820 ppm |
| 2018-11-06 | Y183170033 | 0.850 ppm |
| 2018-12-04 | Y183440016 | 0.590 ppm |
| 2019-01-08 | Y190140026 | 0.420 ppm |
| 2019-02-05 | Y190420022 | 0.570 ppm |
| 2019-03-06 | Y190700036 | 0.520 ppm |
| 2019-04-02 | Y190980019 | 0.420 ppm |
| 2019-04-02 | Y190930002 | 0.400 ppm |
| 2019-05-07 | Y191330020 | 0.690 ppm |
| 2019-06-04 | Y191610033 | 0.780 ppm |
| 2019-07-09 | Y191960037 | 0.700 ppm |
| 2019-08-06 | Y192250043 | 0.660 ppm |
| 2019-09-03 | Y192540009 | 0.720 ppm |
| 2019-10-01 | Y192880023 | 0.740 ppm |
| 2019-11-06 | Y193180039 | 0.760 ppm |
| 2019-12-10 | Y193470022 | 0.660 ppm |