Well Water Notebook
Information only, not medical advice. We never say whether your water is safe to drink. Ask a state-certified lab or your local health department. Disclaimer

Last checked:

Uranium and radon in well water

Bedrock in parts of New England and elsewhere releases uranium and radon into wells. They're tested and treated differently. Here's what agencies say, with a source for every claim.

This guide can't tell you whether your water is safe to drink. Radiological results can be confusing, so ask your state's well program to help you read yours.

The standards

EPA's standards for public water systems:1

Contaminant EPA standard
Uranium 30 µg/L
Combined radium-226/228 5 pCi/L
Gross alpha (not including radon and uranium) 15 pCi/L

These are federal standards for public water systems.

Radon in water has no number in the table above. State levels differ: NHDES uses a 2,000 pCi/L radon testing advisory level in its private well data,2 while Vermont's Health Department has set an advisory level of 4,000 pCi/L.8

How common is it?

Radon is mainly an air problem

Vermont's Health Department says showers, laundry and dishwashers can release radon from water into the air, and that the major danger from radon in water is lung cancer from breathing it in once it's released (drinking it also carries a stomach cancer risk over a lifetime).8 Vermont recommends testing your home's air for radon too, before deciding how to reduce radon levels.8 Soil is the most common source of radon in a home.8

Testing

Treatment types Maine CDC lists

Problem Treatment types Notes
Uranium Reverse osmosis Maine CDC notes there is no NSF-certified method to remove uranium.7
Radon Adsorptive media or aeration Aeration requires special maintenance to prevent mineral buildup.7

Before buying, Maine CDC suggests checking certification for the contaminants you have, getting several quotes, and asking about maintenance and warranty.7

Where to get tested and treatment options

Testing: your state's accredited lab list. See Rockingham County, NH, Hillsborough County, NH, Cumberland County, ME and Penobscot County, ME.

Treatment: point-of-use reverse osmosis for uranium; whole-house aeration or adsorptive media for radon.

  1. U.S. EPA, "Radionuclides Rule." https://www.epa.gov/dwreginfo/radionuclides-rule ↩↩

  2. Kernen, B., NHDES, "Private Wells in Portsmouth" (presentation, September 1, 2021; data 2006–August 2020). https://www.portsmouthnh.gov/sites/default/files/2021-09/Portsmouth%20SWAG%20Sep%201%202021%20DES.pdf ↩↩

  3. Maine CDC, "Private Well Water." https://www.maine.gov/dhhs/mecdc/healthy-living/health-and-safety/drinking-water-safety/private-well-water ↩↩↩

  4. NJDEP, "Private Wells: Gross Alpha." https://dep.nj.gov/privatewells/gross-alpha/ ↩

  5. Maine CDC HETL, "HETL Water Testing Kits Available" (PDF). https://www.maine.gov/dhhs/mecdc/sites/maine.gov.dhhs.mecdc/files/Environmental%20Test%20Guide.pdf ↩

  6. NHDES, "Water Testing Guidance for Private Well Users" (April 2026). https://www.des.nh.gov/sites/g/files/ehbemt341/files/documents/labs-private-wells.pdf ↩

  7. Maine CDC, "Quick Guide to Well Water Treatment" (PDF). https://www.maine.gov/dhhs/mecdc/sites/maine.gov.dhhs.mecdc/files/Well-water-treatment8.27.2026.pdf ↩↩↩

  8. Vermont Department of Health, "Radon in Drinking Water." https://www.healthvermont.gov/environment/drinking-water/radon-drinking-water ↩↩↩↩↩

  9. NJDEP, "Private Wells: Private Well Testing Act (PWTA)." https://dep.nj.gov/privatewells/pwta/ ↩