Uranium
U·Affects kidneys, bones
A naturally occurring radioactive metal that leaches into groundwater from uranium-bearing rock. Both chemically toxic to the kidneys and radiologically active in bone.
U
EPA limit
30 µg/L (MCL)
Most at risk
Well-water households, residents of Rocky Mountain and Appalachian regions, areas overlying granite and phosphate-rich bedrock
Found in
Well water
AquaOx filters
Pair with ROPair with under-sink RO
What it does to you
Health effects
Uranium poses a dual threat. Its chemical toxicity damages the proximal tubules of the kidneys, the same structures responsible for filtering blood and reclaiming nutrients. Long-term exposure is associated with elevated urinary protein, glucose, and beta-2-microglobulin, all markers of renal injury.
The radiological side of uranium is slower but equally serious. Uranium isotopes (primarily U-238, U-235, and U-234) emit alpha particles as they decay, and uranium that crosses into the bloodstream is preferentially deposited in bone tissue where it can sit for decades, irradiating nearby cells and elevating the long-term risk of bone cancer and leukemia.
The EPA set the Maximum Contaminant Level at 30 µg/L in 2000 (effective 2003), based primarily on protecting against kidney damage rather than cancer risk. Many private wells in known hotspot regions test above this level.
Where it comes from
How it gets into your water
Uranium is naturally present in trace amounts throughout the Earth's crust, but it concentrates in specific geological formations: granite, shale, and phosphate-rich sedimentary rock. Groundwater moving through these formations dissolves uranium into the water column, especially when the water is oxygenated and slightly alkaline.
US hotspots include the Rocky Mountain states (Colorado, New Mexico, Wyoming, Utah), parts of the northern Plains (the Dakotas, Nebraska), New England granite belts, and Appalachian shale country. Legacy uranium mining and milling operations have also left contaminated groundwater in parts of the Four Corners region and the Texas Panhandle.
Phosphate fertilizer use can add a smaller agricultural contribution, since phosphate rock itself contains uranium that transfers into the finished product.
Granite and shale aquifers
Natural leaching from uranium-bearing bedrock
Phosphate-rich formations
Common in parts of Florida and the Mountain West
Legacy mining and milling
Four Corners, Appalachia, and the Texas Panhandle
Agricultural runoff
Phosphate fertilizers contain trace uranium
Find out for yourself
Is it in your water?
Public water utilities are required to test for uranium under the EPA Radionuclides Rule, with results reported in each utility's annual Consumer Confidence Report. If your home is on a public system, check the CCR before assuming you have an issue.
Private well owners are responsible for their own testing. The EPA recommends testing for uranium at least once if your well sits in a known hotspot region. Most state environmental health departments offer subsidized radiological testing, and certified labs run standard uranium panels for $30 to $80. The EPA maintains regional radon and uranium occurrence maps that are a good first reference.
The fix
How AquaOx filters it
Uranium is one of the contaminants where the standard AquaOx whole-house carbon and KDF media is not the right tool. Effective uranium filtration requires anion exchange resin or reverse osmosis, neither of which is part of the whole-house system.
For households on uranium-affected wells, we recommend pairing AquaOx with an under-sink reverse osmosis unit at the kitchen tap. RO reliably rejects uranium at the membrane along with the broader inorganic load. Drinking and cooking water account for the vast majority of ingestion exposure, so a point-of-use RO is the cost-effective intervention.
Always test first to confirm the concentration and isotope mix before selecting equipment. Your state environmental health department is the right starting point.