Uranium
A naturally occurring radioactive metal in groundwater. The kidney damage matters more than the radioactivity.
- Safe range
- 0 – 0.03 mg/L (US EPA primary standard, set on kidney toxicity rather than on radioactivity; the health goal beneath it is zero.)
- Ideal range
- 0 mg/L
- Measured in
- mg/L
What it is
Uranium occurs naturally in granite, shale and some sandstone, and dissolves into the groundwater passing through them. Wells in those geologies can carry it without any industrial source nearby.
Why it matters
Uranium is both a radionuclide and a heavy metal, and it is the metal half that drives the drinking water limit: it is toxic to the kidneys at concentrations well below where the radioactivity becomes the main concern. Like arsenic, it is tasteless and invisible, and the health goal is zero, so any detection is worth knowing about even in compliant water.
How to measure it
A laboratory. Uranium is not on any home kit, is not part of a standard well panel, and has to be asked for by name.
Certified laboratory, mail-in kit
- How trustworthy
- Reference grade
- Cost
- Most expensive
- Effort
- Careful sampling, then days or weeks of waiting
You are posted bottles and instructions, you fill them exactly as told, and you post them back. Weeks later a report arrives with figures nobody has to interpret by eye. This is what a result you intend to act on should be built from.
Order it specifically, or buy a radiological panel that includes gross alpha. It is not in a basic well test and it is not in most metals panels either.
Watch out: A gross alpha screen can miss uranium or over-report it depending on the method and the holding time. If gross alpha comes back elevated, ask for uranium measured directly rather than inferred.
Where to find it: State-certified drinking water laboratories; your state's certification officer keeps the list, and many public health departments will point you at one.
Your utility's annual water quality report
- How trustworthy
- Reference grade
- Cost
- Free
- Effort
- A few minutes of reading
Every community water system in the US has to publish one each year, free, listing what it found and what the limits are. It is real laboratory data about the water leaving the plant and travelling the mains. What it cannot describe is your own plumbing.
Public systems monitor for it under the radionuclide rules and publish the result. On mains water, the annual report is the answer.
Where to find it: Your water bill, your supplier's website, or the EPA's index of reports. It is also called a Consumer Confidence Report or CCR.
Further reading: US EPA: National Primary Drinking Water Regulations, the enforceable health-based limits; US EPA: certified drinking water laboratories, by state
If it is too low
No detectable uranium. Nothing to act on.
- • Nothing. Retest periodically if your well is in granite country.
If it is too high
Kidney toxicity is the primary risk from long-term consumption, with a smaller added cancer risk from the radioactivity.
- • Reverse osmosis at the kitchen tap removes it well and is the usual answer for drinking and cooking water.
- • Anion exchange treats the whole house where that is wanted, but produces a waste stream that needs handling properly.
- • Test for radon in air and water at the same time; the same geology often supplies both.
Common questions
Is uranium in well water a radiation risk?
Less than people assume. The drinking water limit is set on chemical toxicity to the kidneys, which occurs at lower concentrations than the radiological risk. Treating for the chemical limit deals with both.
Does a water softener remove uranium?
Not reliably. Softeners are cation exchangers and uranium is usually present as a negatively charged complex, so it passes straight through. Reverse osmosis or a purpose-built anion exchange unit is what removes it.
WiseWaterGauge helps you record and understand your own readings. It is not a substitute for a certified laboratory test, and nothing here is medical or regulatory advice. If a health parameter is out of range, confirm it with an accredited lab and speak to your water provider.