Fluoride in New Hampshire well water
In New Hampshire, <1% of 22,028 private wells tested between 2006 and 2020 had fluoride above the New Hampshire guidance level (4 mg/L), according to NH DHHS.
Natural fluoride in bedrock wells can exceed the limit. Above 4 mg/L long-term exposure causes skeletal fluorosis; above 2 mg/L children can develop tooth mottling.
Check your fluoride number
Type the value from your lab report. It is compared to the New Hampshire guidance level and the EPA limit, the same way the full interpretation does it.
Test your New Hampshire well for fluoride
Certified lab analysis of your own tap water, bottles and prepaid return shipping included. The Essential well panel covers arsenic, uranium, nitrate, lead, copper, manganese, iron, sodium and bacteria; radon and PFAS are add-ons.
Order the Tap Score well water test kit, from $209Already tested? Upload the report
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Systems that remove fluoride
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Some links below are affiliate links. If you buy through one, the merchant pays us a commission at no extra cost to you. It does not change which products we list or what the data says.
For fluoride
Under-sink reverse osmosis system
under-sink or countertop, about $300
Look for NSF/ANSI 58 certification listing the contaminant you need removed.
For fluoride
Aquasana SmartFlow reverse osmosis
under-sink or countertop, about $225
Certified to NSF/ANSI 58 and 53 to reduce arsenic (96%, pentavalent), fluoride (90%), lead (99%), nitrate, nitrite and PFOA/PFOS at the kitchen tap, with a remineralizer.
Rather have it installed and sized for your well? Book a free in-home water test with a licensed local company.
Where to get a well tested for fluoride in New Hampshire: certified labs, state programs and prices.
By county, from homeowner tests
Share of private wells above the state guidance level (4 mg/L) in tests homeowners sent to the state lab, 2006 to 2020.
| County | Above state level | Wells tested | Highest |
|---|---|---|---|
| Carroll | 1,910 | 15 mg/L | |
| Grafton | 2,594 | 11 mg/L | |
| Hillsborough | 4,530 | 9.1 mg/L | |
| Sullivan | 754 | 4.9 mg/L | |
| Merrimack | 4,953 | 7.6 mg/L | |
| Belknap | 1,792 | 7.1 mg/L | |
| Cheshire | 743 | 4.5 mg/L | |
| Coos | 490 | 4.2 mg/L | |
| Rockingham | 3,688 | 5.9 mg/L | |
| Strafford | 574 | 3.5 mg/L |
Towns with the highest share above the state level
- Jackson, Carroll County10% of 39 wells
- Conway, Carroll County10% of 73 wells
- Tamworth, Carroll County7% of 128 wells
- Bartlett, Carroll County6% of 34 wells
- Groton, Grafton County6% of 36 wells
- Wolfeboro, Carroll County5% of 124 wells
- Tuftonboro, Carroll County5% of 557 wells
- Madison, Carroll County5% of 65 wells
- Greenfield, Hillsborough County3% of 59 wells
- Sandwich, Carroll County3% of 204 wells
- Grantham, Sullivan County3% of 77 wells
- Campton, Grafton County3% of 201 wells
- Holderness, Grafton County2% of 261 wells
- East Kingston, Rockingham County2% of 47 wells
- Wilton, Hillsborough County2% of 50 wells
- Hillsborough, Hillsborough County2% of 206 wells
- Deering, Hillsborough County2% of 106 wells
- Plymouth, Grafton County2% of 120 wells
- New Hampton, Belknap County2% of 124 wells
- Freedom, Carroll County2% of 62 wells
- Springfield, Sullivan County2% of 62 wells
- Rumney, Grafton County2% of 136 wells
- Wentworth, Grafton County2% of 66 wells
- Ossipee, Carroll County1% of 145 wells
- Thornton, Grafton County1% of 154 wells
By county, from individual samples
Public monitoring samples against the EPA limit (4 mg/L); counties with at least 30 samples.
| County | Above EPA limit | Samples | Detected | Median | Highest |
|---|---|---|---|---|---|
| Carroll | 210 | 90% | 1.2 | 18.7 mg/L | |
| Coos | 173 | 76% | 0.2 | 6.9 mg/L | |
| Belknap | 186 | 90% | 0.4 | 6.23 mg/L | |
| Merrimack | 497 | 85% | 0.3 | 5 mg/L | |
| Hillsborough | 177 | 79% | 0.2 | 4.5 mg/L | |
| Rockingham | 332 | 79% | 0.07 | 5.6 mg/L | |
| Cheshire | 68 | 90% | 0.2 | 3.1 mg/L | |
| Grafton | 240 | 75% | 0.2 | 3.2 mg/L | |
| Sullivan | 48 | 75% | 0.1 | 1.8 mg/L | |
| Strafford | 94 | 66% | 0.1 | 1.5 mg/L |
Sources
- NH DHHS WISDOM private well summaries: Town summaries of private well tests run by the New Hampshire Public Health Laboratories, published by NH DHHS through the WISDOM environmental public health tracking portal. Exceedance shares use New Hampshire guidance levels, which are stricter than EPA for arsenic (5 ug/L), manganese (0.3 mg/L), radon (2,000 pCi/L) and sodium (20 mg/L). Statistics for small counts are suppressed (*). Retrieved September 3, 2026.
- Individual samples from the USGS Water Quality Portal and state monitoring, summarized per geography. fluoride counts and shares are listed on each county and town page with their sources.