Fluoride in Maine well water
In Maine, 2% of 31,960 private wells tested had fluoride above the Maine guideline (2 mg/L), according to Maine CDC.
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 Maine guideline and the EPA limit, the same way the full interpretation does it.
Test your Maine 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 Maine: certified labs, state programs and prices.
By county, from homeowner tests
Share of private wells above the state guidance level (2 mg/L) in tests homeowners sent to the state lab, to .
| County | Above state level | Wells tested | Highest |
|---|---|---|---|
| Hancock | 2,937 | ||
| Oxford | 1,468 | ||
| Franklin | 899 | ||
| York | 2,695 | ||
| Kennebec | 5,015 | ||
| Somerset | 1,078 | ||
| Cumberland | 4,655 | ||
| Androscoggin | 1,582 | ||
| Washington | 1,443 | ||
| Waldo | 1,664 | ||
| Lincoln | 1,981 | ||
| Sagadahoc | 1,246 | ||
| Knox | 819 | ||
| Penobscot | 3,177 | ||
| Aroostook | 951 |
Towns with the highest share above the state level
- Otis, Hancock County32% of 44 wells
- Dedham, Hancock County19% of 79 wells
- Marshfield, Washington County18% of 33 wells
- Surry, Hancock County18% of 146 wells
- Prospect, Waldo County16% of 61 wells
- Fryeburg, Oxford County16% of 50 wells
- Denmark, Oxford County16% of 45 wells
- Kennebunk, York County15% of 92 wells
- Sedgwick, Hancock County15% of 87 wells
- Mariaville, Hancock County14% of 35 wells
- Smithfield, Somerset County13% of 40 wells
- Mechanic Falls, Androscoggin County13% of 32 wells
- Porter, Oxford County12% of 34 wells
- Stockton Springs, Waldo County11% of 36 wells
- Norridgewock, Somerset County11% of 93 wells
- Brownfield, Oxford County11% of 37 wells
- Raymond, Cumberland County10% of 212 wells
- Otisfield, Oxford County9% of 69 wells
- Casco, Cumberland County9% of 151 wells
- Chesterville, Franklin County9% of 93 wells
- Hiram, Oxford County9% of 59 wells
- York, York County8% of 119 wells
- Blue Hill, Hancock County8% of 157 wells
- Biddeford, York County8% of 75 wells
- Ellsworth, Hancock County8% of 431 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 |
|---|---|---|---|---|---|
| Cumberland | 186 | 75% | 0.04 | 4.9 mg/L | |
| Androscoggin | 57 | 79% | 0.1 | 1.41 mg/L | |
| Kennebec | 72 | 78% | 0.3 | 3.3 mg/L | |
| Hancock | 45 | 69% | 0.12 | 3.3 mg/L | |
| Oxford | 126 | 66% | 0.1 | 3.18 mg/L | |
| Penobscot | 55 | 64% | 0.1 | 0.6 mg/L | |
| York | 69 | 59% | 0.1 | 3.7 mg/L | |
| Washington | 60 | 53% | 0 | 1.5 mg/L | |
| Aroostook | 71 | 52% | 0 | 0.4 mg/L | |
| Somerset | 49 | 47% | 0 | 1.4 mg/L |
Sources
- Maine Tracking Network private well summaries: Town summaries of private well tests run by the Maine Health and Environmental Testing Laboratory, published by Maine CDC through the Maine Tracking Network. Shares are against Maine's guideline for each analyte (arsenic 10 ug/L, uranium 30 ug/L, fluoride 2 mg/L, manganese 0.3 mg/L, nitrate 10 mg/L, nitrite 1 mg/L). Towns with too few tests are suppressed (NR). Only the share above the guideline and wells tested are published; no medians. 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.