Know Your Environment. Protect Your Health.

Fluoride

Regional Water Authority

Fluoride occurs naturally in surface and groundwater and is also added to drinking water by many water systems to prevent cavities and support oral health in people.

In 2015, the Department of Health and Human Services updated its recommendation of an optimal level of 0.7 parts per million, or ppm, added to drinking water based on the health benefits of tooth decay prevention. Studies have shown that fluoride added to community water systems at this level reduces dental cavities, especially in children.

And studies have conclusively shown that fluoride in toothpaste and mouthwash can also provide these benefits. Read More.

Health Concerns

Although the HHS-recommended level of 0.7 ppm can help promote oral health in children and adults, this level is likely too high for bottle-fed babies. EWG recommends that caregivers mix baby formula with fluoride-free water.

And fluoride in water at higher levels can be detrimental for everyone, especially children.

Long-term ingestion of higher levels of fluoride in water increases dental fluorosis, which includes mottling, pitting and weakening of the teeth in children.

A 2024 authoritative assessment by the National Toxicology Program found that higher levels of fluoride exposure, such as drinking water containing more than 1.5 ppm of fluoride, are associated with lower IQ in children. The conclusion was based on studies in human populations outside of the U.S.

Affecting systems with naturally occurring fluoride, 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 fracture. But these effects may occur at lower levels of exposure, raising concerns that the current limit may not adequately protect public health.

 

257

Samples

0

Samples exceeding legal limit (MCL)

0

Samples exceeding
health guidelines

Testing results - average by year

 
YearAverage resultSamples takenDetectionsRange of results
20180.262 ppm26260.0300 ppm - 0.790 ppm
20190.367 ppm26260.0300 ppm - 2.32 ppm
20200.267 ppm259ND - 0.900 ppm
20210.243 ppm2911ND - 0.780 ppm
20220.588 ppm136130ND - 0.860 ppm
20230.524 ppm1511ND - 0.805 ppm

ppm = parts per million

State, National, and Health Guidelines for Drinking Water

EPA Maximum Contaminant
Level (MCL): 4 ppm

ppm = parts per million

All test results

Date Lab ID Result
2018-03-12IOCR 2004897600.0400 ppm
2018-03-12IOCR 2004897580.0900 ppm
2018-03-12IOCR 2004897590.0400 ppm
2018-03-12IOCR 2004897670.0400 ppm
2018-03-14IOCR 2004899110.0800 ppm
2018-03-14IOC1 2004898670.630 ppm
2018-03-14IOC1 2004898700.630 ppm
2018-03-14IOC1 2004898680.760 ppm
2018-03-14IOC1 2004898840.630 ppm
2018-03-14IOC1 2004898850.610 ppm
2018-03-14IOC1 2004898710.660 ppm
2018-03-14IOC1 2004899130.790 ppm
2018-03-14IOC1 2004899140.680 ppm
2018-03-14IOCR 2004898980.0400 ppm
2018-03-14IOCR 2004899000.0500 ppm
2018-03-14IOCR 2004898960.0300 ppm
2018-03-14IOCR 2004899120.0700 ppm
2018-03-14IOCR 2004898860.0500 ppm
2018-03-14IOCR 2004898870.0500 ppm
2018-03-14IOCR 2004898720.0300 ppm
2018-03-14IOCR 2004898970.0400 ppm
2018-03-15IOC1 2004900610.570 ppm
2018-03-15IOCR 2004900620.0700 ppm
2018-03-15IOCR 2004900630.0500 ppm
2018-11-29IOC1 2005141120.0600 ppm
2018-11-29IOCR 2005141140.0300 ppm
2019-03-18IOC1 2005248950.610 ppm
2019-03-18IOCR 2005248960.0400 ppm
2019-03-18IOCR 2005249030.0500 ppm
2019-03-18IOCR 2005249010.0600 ppm
2019-03-18IOCR 2005249020.0400 ppm
2019-03-18IOCR 2005249050.0400 ppm
2019-03-18IOCR 2005249000.0600 ppm
2019-03-19IOCR 2005250950.0800 ppm
2019-03-19IOC1 2005250570.650 ppm
2019-03-19IOC1 2005250600.640 ppm
2019-03-19IOC1 2005250580.690 ppm
2019-03-19IOC1 2005250590.670 ppm
2019-03-19IOC1 2005250770.540 ppm
2019-03-19IOC1 2005250780.610 ppm
2019-03-19IOC1 2005250610.710 ppm
2019-03-19IOC1 2005250970.730 ppm
2019-03-19IOC1 2005250980.620 ppm
2019-03-19IOCR 2005250650.0300 ppm
2019-03-19IOCR 2005250660.0400 ppm
2019-03-19IOCR 2005250640.0500 ppm
2019-03-19IOCR 2005250960.0900 ppm
2019-03-19IOCR 2005250790.0300 ppm
2019-03-19IOCR 2005250800.0400 ppm
2019-03-19IOCR 2005250620.0500 ppm
2019-05-08IOC1 2005312972.32 ppm
2019-05-08IOCR 2005313030.0500 ppm
2020-02-10IOC1 2005654600.650 ppm
2020-02-10IOCR 200565461ND
2020-02-10IOCR 200565469ND
2020-02-10IOCR 200565466ND
2020-02-10IOCR 200565467ND
2020-02-10IOCR 200565470ND
2020-02-11IOC1 2005656240.900 ppm
2020-02-11IOC1 2005656270.680 ppm
2020-02-11IOC1 2005656260.630 ppm
2020-02-11IOC1 2005655930.730 ppm
2020-02-11IOC1 2005656250.760 ppm
2020-02-11IOC1 2005655940.880 ppm
2020-02-11IOC1 200565628A0.720 ppm
2020-02-11IOCR 200565632ND
2020-02-11IOCR 200565633ND
2020-02-11IOCR 200565631ND
2020-02-11IOC1 2005656280.720 ppm
2020-02-11IOCR 200565595ND
2020-02-11IOCR 200565596ND
2020-02-11IOCR 200565629ND
2020-02-12IOCR 200565847ND
2020-02-12IOCR 200565848ND
2020-08-10IOCR 200585597ND
2020-08-11IOCR 200585735ND
2020-08-11IOCR 200585736ND
2021-02-08IOCR 200605858ND
2021-02-08IOCR 200605854ND
2021-02-08IOCR 200605856ND
2021-02-08IOCR 200605852ND
2021-02-08IOCR 200605855ND
2021-02-09IOC1 2006061140.570 ppm
2021-02-09IOC1 2006061110.500 ppm
2021-02-09IOC1 2006061100.610 ppm
2021-02-09IOC1 2006061090.650 ppm
2021-02-09IOC1 2006059560.630 ppm
2021-02-09IOC1 2006058860.780 ppm
2021-02-09IOC1 2006058880.720 ppm
2021-02-09IOC1 2006061160.610 ppm
2021-02-09IOC1 2006059590.720 ppm
2021-02-09IOC1 2006059330.600 ppm
2021-02-09IOCR 200606115ND
2021-02-09IOCR 200606112ND
2021-02-09IOCR 200606113ND
2021-02-09IOCR 200605957ND
2021-02-09IOCR 200605958ND
2021-02-09IOCR 200605931ND
2021-02-09IOCR 200605887ND
2021-02-09IOCR 200605960ND
2021-02-09IOCR 200605889ND
2021-02-09IOCR 200606117ND
2021-02-10IOCR 200606359ND
2021-02-10IOCR 200606356ND
2021-02-17IOCR 200606910ND
2021-02-17IOC1 2006069090.650 ppm
2022-02-01E300138473 3001384750.600 ppm
2022-02-01E300138468 3001384700.540 ppm
2022-02-01E300138463 3001384650.500 ppm
2022-02-01E300139124 3001391260.560 ppm
2022-02-01E300138212 3001382140.540 ppm
2022-02-01E300138222 3001382240.660 ppm
2022-02-01E300138478 3001384800.780 ppm
2022-02-01E300138489 3001384910.680 ppm
2022-02-02E300139291 3001392930.590 ppm
2022-02-02E300139288 3001392900.540 ppm
2022-02-02E300139285 3001392870.480 ppm
2022-02-02E300139632 3001396340.610 ppm
2022-02-02E300139092 3001390940.790 ppm
2022-02-02E300139095 3001390970.700 ppm
2022-02-02E300139297 3001392990.650 ppm
2022-02-02E300139311 3001393130.690 ppm
2022-02-03E300140006 3001400080.550 ppm
2022-02-03E300140003 3001400050.490 ppm
2022-02-03E300139786 3001397880.830 ppm
2022-02-03E300140026 3001400280.660 ppm
2022-02-03E300140018 3001400200.640 ppm
2022-02-04E300140160 3001401620.540 ppm
2022-02-04E300140157 3001401590.500 ppm
2022-02-04E300140154 3001401560.480 ppm
2022-02-04E300140151 3001401530.610 ppm
2022-02-04E300140145 3001401470.830 ppm
2022-02-04E300140148 3001401500.730 ppm
2022-02-04E300140142 3001401440.660 ppm
2022-02-04E300140139 3001401410.700 ppm
2022-02-07E300141157 3001411590.530 ppm
2022-02-07E300141166 3001411680.530 ppm
2022-02-07E300141160 3001411620.450 ppm
2022-02-07E300141163 3001411650.600 ppm
2022-02-07E300141145 3001411470.860 ppm
2022-02-07E300141148 3001411500.700 ppm
2022-02-07E300141169 3001411710.680 ppm
2022-02-07E300141207 300141209ND
2022-02-08E300141653 3001416550.540 ppm
2022-02-08E300141648 3001416500.530 ppm
2022-02-08E300141643 3001416450.440 ppm
2022-02-08E300141638 3001416400.590 ppm
2022-02-08E300141595 3001415970.480 ppm
2022-02-08E300141960 3001419620.760 ppm
2022-02-08E300141970 3001419720.690 ppm
2022-02-08E300141661 3001416630.640 ppm
2022-02-08E300141669 3001416710.670 ppm
2022-02-09E300142548 3001425500.480 ppm
2022-02-09E300142545 3001425470.460 ppm
2022-02-09E300142542 3001425440.570 ppm
2022-02-09E300142722 3001427240.720 ppm
2022-02-09E300142557 3001425590.620 ppm
2022-02-09E300142571 3001425730.630 ppm
2022-02-10E300143103 3001431050.520 ppm
2022-02-10E300143100 3001431020.490 ppm
2022-02-10E300143403 3001434050.740 ppm
2022-02-10E300143409 3001434110.690 ppm
2022-02-10E300143126 3001431280.680 ppm
2022-02-10E300143118 3001431200.560 ppm
2022-02-11E300144356 3001443580.550 ppm
2022-02-11E300144353 3001443550.510 ppm
2022-02-11E300144347 3001443490.830 ppm
2022-02-11E300144350 3001443520.670 ppm
2022-02-11E300144344 3001443460.610 ppm
2022-02-11E300144341 3001443430.500 ppm
2022-02-14E300144715 3001447170.510 ppm
2022-02-14E300144703 3001447050.670 ppm
2022-02-14E300144845 3001448470.790 ppm
2022-02-14E300144850 3001448520.700 ppm
2022-02-15E300145541 3001455430.420 ppm
2022-02-15E300145532 3001455340.500 ppm
2022-02-15E300145523 3001455250.500 ppm
2022-02-15E300145514 3001455160.630 ppm
2022-02-15E300146276 3001462780.530 ppm
2022-02-15E300145647 3001456490.650 ppm
2022-02-15E300145667 3001456690.670 ppm
2022-02-15E300145550 3001455520.540 ppm
2022-02-15E300145575 3001455770.520 ppm
2022-02-15E300145699 3001457010.670 ppm
2022-02-15E300145718 3001457200.550 ppm
2022-02-15I300145657 300145659ND
2022-02-15I300145585 300145587ND
2022-02-15I300145677 300145679ND
2022-02-15I300145560 300145562ND
2022-02-16E300146580 3001465820.450 ppm
2022-02-16E300146577 3001465790.550 ppm
2022-02-16E300146421 3001464230.770 ppm
2022-02-16E300146444 3001464460.690 ppm
2022-02-16E300146595 3001465970.610 ppm
2022-02-16E300146606 3001466080.570 ppm
2022-02-17E300147156 3001471580.580 ppm
2022-02-17E300147153 3001471550.540 ppm
2022-02-17E300147022 3001470240.740 ppm
2022-02-17E300147028 3001470300.730 ppm
2022-02-17E300147183 3001471850.620 ppm
2022-02-17E300147205 3001472070.670 ppm
2022-02-18E300147715 3001477170.520 ppm
2022-02-18E300147712 3001477140.640 ppm
2022-02-18E300147709 3001477110.520 ppm
2022-02-18E300147845 3001478470.640 ppm
2022-02-18E300147703 3001477050.780 ppm
2022-02-18E300147706 3001477080.710 ppm
2022-02-18E300147700 3001477020.630 ppm
2022-02-18E300147697 3001476990.530 ppm
2022-02-22E300148542 3001485440.580 ppm
2022-02-22E300148537 3001485390.600 ppm
2022-02-22E300148528 3001485300.500 ppm
2022-02-22E300148523 3001485250.660 ppm
2022-02-22E300148248 3001482500.770 ppm
2022-02-22E300148258 3001482600.730 ppm
2022-02-22E300148550 3001485520.650 ppm
2022-02-22E300148703 3001487050.650 ppm
2022-02-23E300148780 3001487820.530 ppm
2022-02-23E300148777 3001487790.550 ppm
2022-02-23E300148774 3001487760.510 ppm
2022-02-23E300148771 3001487730.610 ppm
2022-02-23E300149000 3001490020.720 ppm
2022-02-23E300149003 3001490050.730 ppm
2022-02-23E300148783 3001487850.660 ppm
2022-02-23E300148791 3001487930.660 ppm
2022-02-24E300149334 3001493360.520 ppm
2022-02-24E300149331 3001493330.630 ppm
2022-02-24E300149328 3001493300.500 ppm
2022-02-24E300149325 3001493270.650 ppm
2022-02-24E300149675 3001496770.540 ppm
2022-02-24E300149536 3001495380.700 ppm
2022-02-24E300149542 300149544ND
2022-02-24E300149351 3001493530.660 ppm
2022-02-24E300149343 3001493450.640 ppm
2022-02-28E300150035 3001500370.540 ppm
2022-02-28E300150295 3001502970.560 ppm
2022-02-28E300150038 3001500400.490 ppm
2022-02-28E300150041 3001500430.540 ppm
2022-02-28E300150283 3001502850.840 ppm
2022-02-28E300150286 3001502880.680 ppm
2022-02-28E300150044 3001500460.670 ppm
2022-02-28E300150071 3001500730.650 ppm
2023-02-06E300305466 3003054940.805 ppm
2023-02-06E300305519 3003055210.805 ppm
2023-02-07E300305797 3003057990.700 ppm
2023-02-07I300305807 300305809ND
2023-02-14E300309461 3003094630.713 ppm
2023-02-14E300309762 3003097640.706 ppm
2023-02-14E300309452 3003094540.631 ppm
2023-02-14E300309097 3003090990.710 ppm
2023-02-14E300309470 3003094720.700 ppm
2023-02-14E300309495 3003094970.650 ppm
2023-02-14E300309531 3003095330.794 ppm
2023-02-14E300309550 3003095520.648 ppm
2023-02-14I300309505 300309507ND
2023-02-14I300309107 300309109ND
2023-02-14I300309480 300309482ND