Uranium in Well Water: What Your Test Result Actually Tells You
Uranium doesn't announce itself. The Connecticut Department of Public Health describes it plainly as "a metal that has no smell or taste," and the U.S. Environmental Protection Agency explains that uranium, radium and radon occur naturally in rocks and soils and can dissolve into groundwater. A well drilled into uranium-bearing bedrock can carry it while the water looks perfectly clear.
So if you're reading this, you probably have a lab report in hand, or you've heard that wells in your area can run high. Either way, the number on that report is the whole story, and it's easy to misread. This guide walks through it in order: the unit your lab used, the benchmark that applies, what else to test, how much of the house actually needs treatment, and how to confirm the fix worked.
Key Takeaways
Check the Unit First
Your Kidneys Are the Main Concern
Drinking Water Is Usually Enough
Test Radon, Then Retest
Step 1: Check Which Unit Your Lab Used
Labs don't all report uranium the same way, and a number that looks alarming in one unit can be ordinary in another. EPA's National Primary Drinking Water Regulations set the uranium limit as a mass: 30 micrograms per liter. Here's how that same limit looks in the units you're likely to see.
| Unit on your report | What it measures | EPA's uranium limit in that unit |
|---|---|---|
| µg/L (micrograms per liter) | Mass of uranium | 30 µg/L |
| ppb (parts per billion) | Mass, the same scale as µg/L in water | 30 ppb |
| mg/L (milligrams per liter) or ppm | Mass, 1,000 times larger unit | 0.030 mg/L |
| pCi/L (picocuries per liter) | Radioactivity of the uranium | About 20 pCi/L, using EPA's screening factor |
| Gross alpha, pCi/L | Total alpha radiation from every alpha emitter in the sample, uranium included | Not a uranium number; it can't be converted to µg/L |
The pCi/L row needs a little explanation. EPA's compliance guide for radionuclides tells water systems to "simply divide the result in picoCuries by 0.67," which gives "a conservatively high mass number in micrograms." It's a screening shortcut that errs on the high side. If a converted number lands near 30, ask the lab for a uranium result reported directly in µg/L before you make a decision.
The gross alpha row needs the same care. A gross alpha test counts alpha radiation from everything in the sample, uranium included, without saying how much of it came from uranium. EPA's Radionuclides Rule sets its 15 pCi/L gross alpha standard "not including radon and uranium," and uranium has its own 30 µg/L limit. Federal monitoring rules do let a public water system substitute a gross alpha measurement of 15 pCi/L or less for its uranium test, according to 40 CFR 141.26, but a gross alpha number still can't be turned into a uranium level. If that's all you have, ask the lab for a uranium result in µg/L.
If you haven't tested yet, Connecticut's health department recommends asking a certified lab for a uranium test by ICP-MS, a method it notes is quicker and less expensive than the alternatives. Crystal Quest®'s Uranium Water Test ($79) is analyzed by our partner lab, National Testing Laboratories, and reports down to 0.001 mg/L. That's 1 µg/L, a thirtieth of the federal limit.
Step 2: Compare Your Number to the Right Benchmark
EPA's enforceable limit for uranium is 30 µg/L, and its non-enforceable health goal is zero. The agency's regulation table lists the potential health effects as "increased risk of cancer, kidney toxicity," with erosion of natural deposits as the source.
The state and university guidance for well owners puts the emphasis somewhere specific. Connecticut's health department says "the chemical properties of uranium in drinking water are of greater concern than its radioactivity." The University of Georgia Extension says drinking water above 30 ppb "may increase the risk of kidney malfunction," and adds that exposure to uranium in drinking water "has not been shown to increase the risk of developing cancer." Those statements fit together. The regulatory table lists potential effects, while the well-owner guidance says which one the evidence points to first. Either way, the kidneys are the reason to take a high result seriously.
| Your uranium result | What it means | Sensible next step |
|---|---|---|
| Not detected | Below the lab's detection level | Test radon too, then retest on EPA's three-year rhythm |
| Detected, under 30 µg/L | Below the public water limit, above EPA's zero health goal | Retest to confirm, test radon, and decide how much margin you want |
| Above 30 µg/L | Over the limit a public system must meet | Treat drinking and cooking water, test radon and radium |
| Above 900 µg/L | Thirty times the limit | Call your state or local health department before choosing equipment |
The 900 µg/L line comes from Connecticut's guidance, which advises contacting the health department "about options for a safe water supply to your home" at that level. For a result over 30 µg/L, the same fact sheet is direct: "you will need to treat your water to remove the uranium."
Private Wells Usually Aren't Held to That Limit
The Radionuclides Rule applies to community water systems. EPA's guidance for private wells says, "Well owners are responsible for making sure their drinking water is safe to drink." That 30 µg/L figure is still the best yardstick you've got, but the federal rule doesn't apply to a private well, so testing is usually up to you. Your state or local health department can tell you whether any local rules apply. EPA suggests asking your local drinking water office or radiation control program which tests are most useful in your area, which is free advice worth taking before you spend money on a lab.
Step 3: Test for What Often Travels With Uranium
A uranium result is rarely the last test worth running. The University of Georgia notes that "elevated concentrations of uranium in well water often indicate high levels of radon" in both the water and the indoor air. Here's what to add, and why.
- Radon in water. It's a different problem with a different exposure route, covered in the box below.
- Radium-226 and radium-228. EPA's combined limit for public water is 5 pCi/L. Connecticut's guidance says you can skip a separate radium test if you're installing a uranium system that also removes radium.
- Uranium directly, if all you have is gross alpha. As covered above, a gross alpha number can't be converted into a uranium level.
EPA's Consumer's Guide to Radon Reduction explains that "most of your risk from radon in water comes from radon released into the air when water is used for showering and other household purposes." That's why radon is treated where water enters the home, usually with granular activated carbon or an aeration system. A filter that treats only your kitchen tap for uranium won't address radon from your shower.
Crystal Quest's Radiological Water Test bundles these. The Basic tier ($179) covers uranium, gross alpha and gross beta. Standard ($219) adds radon-222, and Deluxe ($565) adds radium-226 and radium-228. If uranium is already confirmed and you only need the radon piece, the Radon Water Test is $69. For the broader list of what a private well should be checked for, see our guide to testing well water.
Step 4: Decide How Much of the House to Treat
This decision drives most of the cost. Connecticut's health department explains that "because uranium gets into your body primarily through ingestion (and not through the skin or through inhalation), it is not usually necessary to treat all the water in your home, but only the water you drink." It also says bathing and showering with uranium-bearing water "is not a health concern unless uranium levels are extremely high."
Treating the Water You Drink and Cook With
Federal rules name ion exchange, reverse osmosis, lime softening and coagulation/filtration as the best available technologies for uranium at public water systems, and they list point-of-use ion exchange, point-of-use reverse osmosis and activated alumina among the options for small systems, according to 40 CFR 141.66. At home, Connecticut calls reverse osmosis "the most common type of treatment used for uranium removal" and "very effective." The University of Georgia puts point-of-use RO systems at 5 to 20 gallons of drinking water a day, removing 90 to 99 percent of uranium. Our explainer on what reverse osmosis removes covers how the membrane does it.
Those percentages describe the technology category. Whatever you buy, ask for performance data that names uranium and was measured on the model you're getting.
If you'd rather not run a membrane system, Crystal Quest's Inline Undersink Water Filter 8GPM comes in a SMART + Radium / Uranium package ($345 in fiberglass, $545 in stainless steel) with specialized media designed to reduce radium and uranium. It installs on the cold water line to one sink and treats the cold water that comes out of that tap, so it doesn't need its own faucet. There's no backwash, so the media gets replaced rather than regenerated. We don't publish a uranium removal percentage for it, which is exactly why the retest in Step 5 matters.
When Whole-House Treatment Makes Sense
Treating only the kitchen covers most homes with a uranium problem. It doesn't cover all of them. Point-of-entry treatment earns a closer look when:
- Your result is extreme. At Connecticut's 900 µg/L line, the conversation starts with the health department about a safe supply, not with a filter.
- The water serves more than a household. We've had a ranch bring us certified lab data showing uranium at 327 µg/L, about 11 times the EPA limit, and ask us to engineer treatment for the whole property, household and livestock together.
- You want every tap treated, or radium came back high too and you'd rather handle both in one system.
For those cases, the Radium & Uranium Whole House Water Filter (from $2,389) runs water through a sediment pre-filter, a removal tank of specialized ion exchange media that backwashes automatically, and a carbon post-filter. Be clear about what it isn't: it doesn't remove fluoride, nitrates or total dissolved solids, it needs professional installation and periodic maintenance, and it isn't a radon system. If radon is high, that's a separate carbon or aeration decision.
Ask What Happens to the Uranium the Filter Catches
Treatment moves uranium from your water into something else: a filter, a media bed or a waste stream. The University of Nebraska-Lincoln Extension advises sending the waste collected on treatment filters or adsorbent material to a licensed landfill and checking with professionals about the rules that apply. EPA's radon guide makes a similar point about carbon filters used for radon, which "can collect radioactivity and may require a special method of disposal." Before you buy, ask the seller:
- How is spent media or a used cartridge handled, and who removes it?
- Where does backwash or reject water go, and is that allowed where you live?
- How often does the media need replacing at your uranium level?
Step 5: Test the Treated Water, Then Keep Testing
The University of Georgia is blunt about this: "After installing any home water treatment system for uranium removal, you should retest your water." Draw that sample from the treated tap, not the well. It's the only result that shows the system is working on your water, at your level, and it turns a product description into something you've checked yourself.
After that, keep a rhythm. EPA advises private well owners to test for radionuclides every three years. The Washington State Department of Health adds that you may want to retest after an earthquake or major nearby excavation, such as mining or highway construction. And keep up with media or filter changes on schedule, because a treatment system that's past its life stops being a treatment system. For the bigger picture on what else can turn up in household water, our guide to water contaminants covers the rest.
Start with a number you can trust.
A radiological panel shows your uranium level alongside radon, gross alpha and radium, so you size treatment for the problem you actually have.
Frequently Asked Questions About Uranium in Well Water
Is it safe to shower in well water that has uranium?
Connecticut's well guidance says bathing and showering with water that contains uranium isn't a health concern unless levels are extremely high, because uranium enters the body mainly by drinking it. Radon is different, since its main risk comes from breathing what escapes into the air, so test for it separately.
Does a gross alpha result tell me my uranium level?
No. Gross alpha counts alpha radiation from uranium and other alpha emitters together, so it can't be converted into a uranium level, and EPA's 15 pCi/L gross alpha standard leaves uranium out. Ask the lab for a uranium result, ideally in µg/L, to compare against the 30 µg/L limit.
How often should I test my well for uranium?
EPA advises private well owners to test for radionuclides every three years. Test the treated water once any system is installed, and consider an extra test after an earthquake or major digging nearby.
