Uranium is one of the most dangerous contaminants in well water — and one of the hardest to detect. You cannot see it, smell it, or taste it. The only way to know is a lab test.
The EPA set a strict Maximum Contaminant LevelMCL (Maximum Contaminant Level)The highest level of a contaminant allowed in public drinking water, set by the EPA. Private wells are not regulated by MCLs, but they serve as the best available safety benchmarks.Learn more → (the legal limit for public water systems) of 30 µg/L for uranium[1]. That limit exists because long-term exposure damages kidneys and raises cancer risk. Private well owners are responsible for testing on their own.
Quick Answer
The EPA limit is 30 ppbPPB (Parts Per Billion)A unit of concentration equivalent to micrograms per liter (µg/L). Used for trace contaminants like arsenic, lead, and PFAS where even tiny amounts matter.Learn more → (parts per billion, same as µg/L). Uranium is invisible — a lab test is the only way to detect it. Reverse osmosisReverse Osmosis (RO)A treatment method that forces water through a semipermeable membrane, removing up to 99% of dissolved contaminants including arsenic, lead, fluoride, nitrates, and PFAS.Learn more → (a membrane filtration system) removes 90–99% at the drinking water tap. Anion exchangeIon ExchangeA treatment process where unwanted ions (calcium, magnesium, iron) are swapped for sodium or potassium ions as water passes through a resin bed. The principle behind water softeners.Learn more → (a resin-based system) treats the whole house at 95–98% removal.
What Is Uranium and Why Is It in Your Well?
Uranium is a naturally occurring radioactive metal found in certain types of rock — especially granite, shale, and metamorphic formations. Groundwater dissolves uranium from these rocks the same way it dissolves iron or arsenic.
The difference: iron stains your fixtures. Arsenic is invisible but has clear symptoms over time. Uranium is invisible AND its health effects are slow and cumulative. That makes it easy to ignore — and dangerous to leave untreated.
According to the USGS, more than 2 million Americans on private wells may be exposed to elevated uranium or other geogenic contaminants[4].
Who Is at Risk? High-Uranium Regions
Uranium in well water is not evenly distributed. Your risk depends almost entirely on the bedrock beneath your property.
| Region | Risk Level | Why |
|---|---|---|
| New England (NH, CT, ME, MA) | High | Granite and metamorphic bedrock. NH estimates 76% of the state has detectable uranium in groundwater[5]. |
| Rocky Mountain States (CO, MT, WY, NM) | High | Granitic intrusions and uranium-bearing sedimentary formations. |
| Central California (San Joaquin Valley) | Moderate–High | 24% of wells sampled exceeded 30 µg/L in USGS studies. |
| Pacific Northwest (WA, OR) | Moderate | Granitic bedrock in eastern portions. Some wells in NE Washington measured over 1,000 µg/L. |
| Atlantic/Gulf Coastal Plains | Low | Sedimentary sand and clay formations with minimal uranium content. |
If your home sits on granite or metamorphic rock, test for uranium regardless of symptoms. There are no symptoms until damage is done.
Already have your water test results? Get a personalized treatment recommendation.
Analyze My Water TestHealth Risks of Uranium in Well Water
Uranium is both a chemical toxin and a radioactive element. The primary health concern at drinking water levels is chemical kidney damage — not radiation[3].
Kidney Damage
Uranium accumulates in kidney tissue. Long-term exposure above 30 µg/L can cause tubular damage — the part of the kidney that filters waste from blood. Early kidney damage often shows no symptoms[6].
Cancer Risk
The EPA classifies uranium as having "evidence of potential carcinogenicity" at high exposures[1]. This is why the MCL exists — it's set to limit lifetime cancer risk to below 1 in 10,000.
Vulnerable Populations
Children, pregnant women, and people with existing kidney conditions face greater risk. Infants and formula-fed babies are especially vulnerable because of their low body weight relative to water intake. See our guide on well water safety for babies.
What Your Uranium Level Means
| Level (µg/L) | Status | What It Means | What to Do |
|---|---|---|---|
| 0–10 | Low | Well below EPA limit. Minimal concern. | Retest every 3–5 years. |
| 10–30 | Approaching Limit | Below MCL but elevated. Levels can fluctuate seasonally. | Retest in 6 months. Consider treatment if near 30. |
| 30–100 | Exceeds MCL | Above EPA limit. Kidney risk with long-term exposure. | Install treatment. RO at tap or whole-house anion exchange. |
| 100+ | Priority | Significantly elevated. Use alternative water source immediately. | Switch to bottled water now. Install treatment urgently. |
How to Test for Uranium
Standard well water panels do not include uranium. You must specifically request a uranium or radionuclides test. Many homeowners go years without knowing because they never asked for the right panel.
Order a uranium-specific test from a state-certified lab. Some labs bundle it with a radionuclides panel that also covers radon and radium.
Cost: $25–$60 for uranium alone. $80–$150 for a full radionuclides panel.
When to test:
- If your home is on granite, shale, or metamorphic bedrock
- If you live in New England, the Rockies, or central California
- If a neighbor's well tested positive for uranium
- When buying a home with a private well (add uranium to your inspection panel)
- Every 3–5 years if your area is known for uranium occurrence
3 Ways to Remove Uranium from Well Water
Drinking Water Only: Reverse Osmosis (RO)
A point-of-use reverse osmosisReverse Osmosis (RO)A treatment method that forces water through a semipermeable membrane, removing up to 99% of dissolved contaminants including arsenic, lead, fluoride, nitrates, and PFAS.Learn more → system installed under your kitchen sink removes 90–99% of uranium[7]. This is the most cost-effective option if your main concern is drinking and cooking water.
RO also removes arsenic, lead, nitrates, and other dissolved contaminants.
Cost: $300–$800 installed. Filter replacement: $50–$100/year.
Best for: Households focused on safe drinking water. Quick, affordable solution.
Whole House: Anion Exchange
An anion exchange system works like a water softenerWater SoftenerA system that uses ion exchange resin to remove calcium and magnesium (hardness minerals) from water. Prevents scale buildup in pipes, water heaters, and appliances.Learn more → (a salt-regenerated resin tank) but targets uranium ions instead of calcium. It treats all water entering your home and removes 95–98% of uranium[8].
The resin is regenerated with salt — just like a softener. You'll add salt to a brine tank every few weeks depending on water use.
Cost: $2,500–$4,000 installed. Salt and maintenance: $100–$200/year.
Best for: Homes with very high uranium (100+ µg/L) or families wanting whole-house protection.
Important: Spent resin concentrates uranium. Check your state's disposal requirements before installation. Some states classify spent resin as low-level radioactive waste[8].
Alternative: Adsorptive Media
Newer systems use specialized media (like titanium oxide or iron-based adsorbents) to bind uranium as water passes through. These do not require salt or regeneration — you replace the media cartridge periodically.
Cost: $1,500–$3,000 installed. Media replacement: $200–$400/year.
Best for: Moderate uranium levels (30–80 µg/L). Homeowners who want a low-maintenance option.
What Does NOT Remove Uranium
- Boiling — concentrates uranium (water evaporates, uranium stays)
- Carbon filters — including refrigerator filters and pitcher filters
- Water softeners — standard cation exchange does not target uranium
- UV disinfection — kills bacteria, does nothing to dissolved metals
- Sediment filters — uranium is dissolved, not particulate
DIY vs. Professional Installation
A point-of-use RO system is a straightforward DIY project — most install in 1–2 hours under the kitchen sink with basic tools.
Whole-house anion exchange requires plumbing modifications, drain connections, and potentially electrical work for the control valve. Professional installation is recommended and adds $300–$600.
Regardless of system type: Retest your water 2 weeks after installation to confirm the system is performing correctly. Then retest annually.
What to Do Next
Don't know your level? Order a uranium-specific lab test. Standard panels won't catch it.
Below 30 µg/L? You're under the EPA limit but not risk-free. Retest in 6–12 months — levels fluctuate with seasons and water table depth.
Above 30 µg/L? Install treatment. An under-sink RO is the fastest, most affordable path to safe drinking water.
Above 100 µg/L? Use bottled water immediately while you arrange treatment. Consider whole-house anion exchange.
Have other contaminants too? Use our Water Test Interpreter to get a complete recommendation based on all your results.
Frequently Asked Questions
Is uranium in well water dangerous?
Yes. The EPA set a limit of 30 µg/L because long-term exposure damages kidneys and increases cancer risk[1]. Uranium has no visible signs — a lab test is the only way to know your level.
How do I know if my well has uranium?
You must request a specific uranium test. Standard well water panels do not include it. State-certified labs offer the test for $25–$60. Wells in granite or metamorphic bedrock regions are at highest risk[5].
What removes uranium from well water?
Reverse osmosis removes 90–99% at a single faucet[7]. Anion exchange removes 95–98% whole-house. Both are EPA-recognized treatment methods.
Which states have the most uranium in well water?
New Hampshire, Connecticut, Maine, Colorado, Montana, Wyoming, and parts of California and Washington have the highest rates due to granite and metamorphic bedrock[4].
Does boiling water remove uranium?
No. Boiling concentrates uranium because water evaporates but the dissolved uranium remains. You need reverse osmosis or ion exchange for removal.
References
- U.S. EPA. "Radionuclides Rule." 40 CFR Parts 9, 141, and 142, 2000. https://www.epa.gov/dwreginfo/radionuclides-rule
- U.S. EPA. "National Primary Drinking Water Regulations: Uranium MCL 30 µg/L." 2003. https://www.epa.gov/ground-water-and-drinking-water/national-primary-drinking-water-regulations
- CDC ATSDR. "Uranium Toxicity: Standards and Regulations for Uranium Exposure." 2024. https://archive.cdc.gov/www_atsdr_cdc_gov/csem/uranium/standards.html
- U.S. Geological Survey. "Elevated Geogenic Contaminants Common in Drinking Water Aquifers Across the U.S." 2022. https://www.usgs.gov/mission-areas/water-resources/news/elevated-geogenic-contaminants-common-drinking-water-aquifers
- U.S. Geological Survey. "New Maps Show the Probability for Radon and Uranium in New Hampshire's Groundwater." 2023. https://www.usgs.gov/news/state-news-release/new-maps-show-probability-radon-and-uranium-new-hampshires-groundwater
- WHO. "Uranium in Drinking-Water." Background Document for Guidelines for Drinking-Water Quality, 2012. https://www.who.int
- Nova Scotia Environment. "Removing Uranium From Drinking Water Using Reverse Osmosis." 2022. https://novascotia.ca/nse/water/uraniumremovalro.asp
- National Ground Water Association. "Uranium in Private Wells." Wellowner.org, 2024. https://wellowner.org/resources/water-quality/contaminants/uranium/