Uranium in well water
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private wells tested in Cumberland County, Maine had uranium above the limit, the highest share of any county, according to Maine Tracking Network private well summaries.
Uranium in well water comes from granite bedrock. Its main health effect is chemical toxicity to the kidneys rather than radiation. It is common in the same areas where radon and arsenic occur.
- EPA limit
- 30 ug/L (EPA MCL (40 CFR 141.66))
- Maine level
- 30 ug/L
- CAS number
- 7440-61-1
Check your uranium number
Type the value from your lab report. It is compared to the EPA limit, the same way the full interpretation does it.
Test your own well for uranium
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 uranium
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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 uranium
Under-sink reverse osmosis system
under-sink or countertop, about $300
Look for NSF/ANSI 58 certification listing the contaminant you need removed.
For uranium
Whole-house arsenic and uranium filter
whole-house, at the point of entry, about $2,500
Adsorptive iron-based media; sized to your well yield.
Rather have it installed and sized for your well? Book a free in-home water test with a licensed local company.
Where uranium is worst, by homeowner tests
Counties ranked by the share of private wells above the state guidance level in tests homeowners sent to the state lab. Shares combine town summaries, weighted by wells tested.
| County | Above state level | Wells tested | Highest |
|---|---|---|---|
| Cumberland County, Maine | 3,441 | ||
| Androscoggin County, Maine | 1,016 | ||
| Wake County, North Carolina | 411 | 1,970 ug/L | |
| Oxford County, Maine | 953 | ||
| Hancock County, Maine | 2,264 | ||
| Sullivan County, New Hampshire | 619 | 1,600 ug/L | |
| Lincoln County, Maine | 1,490 | ||
| Waldo County, Maine | 1,191 | ||
| Forsyth County, North Carolina | 96 | 92 ug/L | |
| Orleans County, Vermont | 768 | 893 ug/L | |
| Kennebec County, Maine | 4,005 | ||
| Merrimack County, New Hampshire | 4,248 | 3,340 ug/L | |
| Carroll County, New Hampshire | 1,701 | 420 ug/L | |
| Rockingham County, New Hampshire | 2,790 | 860 ug/L | |
| Hillsborough County, New Hampshire | 3,323 | 584 ug/L |
By individual samples
Counties with at least 30 individual samples in public monitoring data, against the EPA limit.
| County | Above EPA limit | Samples | Detected | Median |
|---|---|---|---|---|
| Logan County, Colorado | 31 | 100% | 75 ug/L | |
| Morgan County, Colorado | 60 | 92% | 41.5 ug/L | |
| Montrose County, Colorado | 103 | 96% | 64.1 ug/L | |
| Arapahoe County, Colorado | 651 | 95% | 35.6 ug/L | |
| Stevens County, Washington | 751 | 100% | 39.6 ug/L | |
| Stark County, North Dakota | 55 | 98% | 43 ug/L | |
| Denver County, Colorado | 42 | 95% | 32.4 ug/L | |
| Mesa County, Colorado | 43 | 98% | 30 ug/L | |
| Fremont County, Colorado | 57 | 96% | 27 ug/L | |
| Goshen County, Wyoming | 38 | 97% | 21.1 ug/L | |
| Billings County, North Dakota | 51 | 94% | 12 ug/L | |
| Cibola County, New Mexico | 120 | 98% | 10.3 ug/L | |
| Churchill County, Nevada | 392 | 97% | 3.19 ug/L | |
| Carson City County, Nevada | 133 | 97% | 12.4 ug/L | |
| Kings County, California | 130 | 98% | 5.35 ug/L |
How to test
Use a state-certified lab and a proper sampling bottle; hardware-store strips cannot measure uranium at the levels that matter. Collect from the kitchen tap before any treatment, and again after treatment if you install it.
How to treat
- Point-of-use reverse osmosis
- Anion exchange
- Whole-house anion exchange