Fluoride
Carson City Public Works
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 | 0.537 ppm | 26 | 24 | ND - 2.80 ppm |
| 2015 | 0.572 ppm | 14 | 11 | ND - 1.60 ppm |
| 2016 | 0.760 ppm | 7 | 6 | ND - 1.50 ppm |
| 2017 | 0.667 ppm | 29 | 27 | ND - 1.70 ppm |
| 2018 | 0.370 ppm | 7 | 5 | ND - 1.70 ppm |
| 2019 | 0.344 ppm | 5 | 4 | ND - 1.40 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 |
|---|---|---|
| 2014-05-27 | 201405280593-N | ND |
| 2014-06-19 | 201406200194 | 1.20 ppm |
| 2014-06-19 | 201406200195 | 0.0730 ppm |
| 2014-06-19 | 201406200119 | 0.380 ppm |
| 2014-06-19 | 201406200121 | 1.40 ppm |
| 2014-06-19 | 201406200120 | 1.10 ppm |
| 2014-06-19 | 201406200196 | 0.0610 ppm |
| 2014-06-24 | 201406250086 | 0.260 ppm |
| 2014-06-24 | 201406250085 | 0.0610 ppm |
| 2014-06-24 | 201406250088 | 0.170 ppm |
| 2014-06-24 | 201406250087 | 0.150 ppm |
| 2014-06-24 | 201406250083 | 0.110 ppm |
| 2014-06-24 | 201406250084 | 0.240 ppm |
| 2014-06-25 | 201406260269 | 0.0520 ppm |
| 2014-06-25 | 201406260270 | ND |
| 2014-06-25 | 201406260268 | 0.0540 ppm |
| 2014-06-25 | 201406260267 | 0.310 ppm |
| 2014-07-01 | 201407020366 | 0.0550 ppm |
| 2014-07-01 | 201407020365 | 1.40 ppm |
| 2014-07-01 | 201407020367 | 0.0580 ppm |
| 2014-07-08 | 201407090717 | 0.0540 ppm |
| 2014-07-30 | 201407310263 | 0.0600 ppm |
| 2014-09-04 | 1409107-003 | 1.40 ppm |
| 2014-09-04 | 1409107-002 | 0.920 ppm |
| 2014-09-04 | 201409050261 | 1.60 ppm |
| 2014-09-04 | 1409107-001 | 2.80 ppm |
| 2015-05-06 | 150506-008 | 1.60 ppm |
| 2015-06-03 | 1506119-001 | 1.30 ppm |
| 2015-06-29 | 201506300124-IOC | 1.10 ppm |
| 2015-06-29 | 201506300177-IOC | 0.510 ppm |
| 2015-06-30 | 201507010220-IOC | 0.740 ppm |
| 2015-07-01 | 1507048-001 | 1.60 ppm |
| 2015-07-14 | 201507150299 | ND |
| 2015-07-15 | 201507160598 | ND |
| 2015-07-15 | 201507160441 | 0.0520 ppm |
| 2015-07-15 | 201507160255 | 0.440 ppm |
| 2015-08-04 | 201508050327 | 0.190 ppm |
| 2015-08-10 | 201508110263 | 0.140 ppm |
| 2015-09-15 | 201509020134 | 0.330 ppm |
| 2015-09-24 | 201509250182 | ND |
| 2016-06-22 | 201606230265 | ND |
| 2016-06-22 | 201606230267 | 0.330 ppm |
| 2016-06-22 | 201606230270 | 0.330 ppm |
| 2016-06-27 | 1606830-001 | 1.50 ppm |
| 2016-07-18 | 160718-001 | 1.50 ppm |
| 2016-08-10 | 201608110453 | 1.30 ppm |
| 2016-08-10 | 201608110350 | 0.360 ppm |
| 2017-05-15 | 201705160867 | 0.0760 ppm |
| 2017-05-15 | 201705160571 | 0.220 ppm |
| 2017-05-15 | 201705160632 | 0.0720 ppm |
| 2017-05-16 | 201705170491 | 1.20 ppm |
| 2017-05-16 | 201705170304 | 1.30 ppm |
| 2017-05-23 | 201705240962 | 0.180 ppm |
| 2017-05-25 | 201705260591 | 0.160 ppm |
| 2017-06-06 | 170606-022 | 1.50 ppm |
| 2017-06-20 | 201706210537 | 0.0680 ppm |
| 2017-06-20 | 201706210725 | 0.0640 ppm |
| 2017-07-05 | 1707051-002 | 1.50 ppm |
| 2017-07-05 | 201707060865 | 0.0720 ppm |
| 2017-07-19 | 201707200814 | 1.30 ppm |
| 2017-07-20 | 201707210331 | 0.110 ppm |
| 2017-07-20 | 201707210328 | 0.190 ppm |
| 2017-07-25 | 201707260764 | ND |
| 2017-07-25 | 201707260654 | 0.310 ppm |
| 2017-07-25 | 201707260765 | ND |
| 2017-07-26 | 201707260490 | 0.0540 ppm |
| 2017-07-27 | 201707280313 | 1.60 ppm |
| 2017-08-01 | 201708021436 | 0.600 ppm |
| 2017-08-01 | 201708020922 | 0.320 ppm |
| 2017-08-01 | 201708020897 | 0.0660 ppm |
| 2017-08-02 | 170802-001 | 1.40 ppm |
| 2017-08-28 | 201708290217 | 0.390 ppm |
| 2017-09-06 | 170906_007 | 1.70 ppm |
| 2017-10-04 | 171004-001 | 1.50 ppm |
| 2017-11-01 | 1711043-001 | 1.70 ppm |
| 2017-12-06 | 1712200-001 | 1.70 ppm |
| 2018-01-03 | 1801092-001 | 1.70 ppm |
| 2018-04-25 | 18041332-01 | 0.200 ppm |
| 2018-05-15 | 201805160828 | ND |
| 2018-05-15 | 201805161020 | ND |
| 2018-05-24 | 201805250730 | 0.0640 ppm |
| 2018-05-30 | 201805310461 | 0.530 ppm |
| 2018-07-23 | 201807240376 | 0.0990 ppm |
| 2019-06-24 | 201906250202A | ND |
| 2019-08-21 | 201908220455 | 0.000180 ppm |
| 2019-08-22 | 201908230324 | 0.000370 ppm |
| 2019-09-24 | 201909250291 | 1.40 ppm |
| 2019-09-25 | 201909260166 | 0.320 ppm |