How to Remove Radium from Drinking Water
What Is Radium and Why Does It Appear in Drinking Water?
Radium is a radioactive alkaline earth metal — element 88 on the periodic table — that occurs naturally in trace amounts in rocks and soil throughout the earth's crust. Unlike lead or PFAS, which are industrial contamination problems, radium in drinking water is almost entirely geological in origin. It has nothing to do with nuclear power plants or industrial discharge. The same geology that makes some regions geologically interesting — granite outcroppings, ancient sandstone aquifers, deep shale formations — is what puts radium into groundwater.
Radium decays into radon gas, which is the second-leading cause of lung cancer in the US (after smoking). The decay chain matters: radium-226 decays to radon-222, which is the radon gas associated with indoor air quality concerns. Radium-228 decays through a different chain with different radiation characteristics. Both isotopes are covered under the EPA's 5 pCi/L combined MCL, though they have different biological behaviors — radium-226 emits alpha radiation and accumulates in bone; radium-228 emits beta radiation with longer tissue penetration. For water treatment purposes, both are addressed by the same methods.
Municipal utilities serving communities in high-radium geology are required to test and treat. Private well owners are not. An estimated 30–40% of private wells in radium-bearing regions have never been tested for radioactivity. If you are on well water in Illinois, Wisconsin, Texas, Ohio, or New England, and you have not tested for radium, stop reading and order a test.
Health Effects of Radium Exposure
Radium is chemically similar to calcium. This is the core of its toxicological problem: when ingested, the body cannot distinguish radium from calcium, and deposits it in bone tissue where it remains, continuing to emit ionizing radiation, for years to decades. The health effects of radium exposure are documented from multiple sources:
Bone cancer (osteosarcoma)
Radium-226 deposits in bone and emits alpha particles that damage bone marrow DNA over years. The "Radium Girls" — factory workers who painted luminous clock dials with radium-based paint in the 1920s and ingested radium while licking their brushes — developed bone cancers at dramatically elevated rates, establishing the bone-seeking, carcinogenic nature of radium.
Risk threshold: No safe threshold — effects are dose-dependent; the EPA MCLG is 0 pCi/L
Kidney damage
Radium is processed through the kidneys before being deposited in bone. High-dose exposure causes direct kidney damage. Chronic low-level exposure at concentrations found in some private wells has been associated with elevated kidney cancer rates in epidemiological studies of Illinois communities.
Risk threshold: Risk increases with concentration and duration of exposure
Anemia
Radiation damage to bone marrow from radium deposition impairs red blood cell production. This was a primary symptom in occupationally-exposed radium workers and is documented at high-dose exposures.
Risk threshold: More relevant at occupational exposures; drinking water risk is chronic low-dose
US Regions with Elevated Radium in Drinking Water
| Region | Geology | Primary Isotope | Risk Level |
|---|---|---|---|
| Illinois (central/southern) | Cambrian sandstone aquifer | Ra-226 + Ra-228 | High — some wells 20+ pCi/L |
| Wisconsin (eastern) | Precambrian basement rock | Ra-226 + Ra-228 | High — documented health studies |
| Texas (Permian Basin, Hill Country) | Carbonate rock formations | Ra-226 | Moderate–High |
| New England (ME, NH, VT) | Granite bedrock | Ra-226 | Moderate — highly variable by location |
| Ohio (north) | Ordovician carbonates | Ra-226 | Moderate |
| Idaho, Montana (mining areas) | Various mineral-bearing formations | Ra-226 | Variable — uranium mining history |
How to Remove Radium from Drinking Water
Radium treatment requires either point-of-use filtration (kitchen tap and drinking water) or whole-house treatment. The appropriate choice depends on your radium concentration, budget, and whether you need protection at all taps or just drinking water. Standard activated carbon filters do not remove radium.
Reverse Osmosis (Point-of-Use)
85–95% radium removalRO membrane physically excludes dissolved radium ions. The most practical solution for most households — protects drinking and cooking water at the kitchen tap.
Best for: households with radium 5–20 pCi/L. Does not address shower or bath exposure.
Water Softener (Cation Exchange)
80–90% radium removalRadium behaves like calcium chemically — it exchanges onto standard softener resin. Effectively removes radium as a side effect of hardness treatment. Used by many Illinois utilities as the primary radium treatment method.
Best for: households with both hard water and radium concerns. Resin regeneration brine contains concentrated radium — disposal per local regulations required.
Strong-Base Anion Exchange
90–99% radium removalSpecifically designed for radium removal (different mechanism than standard cation softeners). More effective but requires specialized equipment and professional installation. Used by utilities serving high-radium communities.
Best for: very high radium levels (>20 pCi/L) or whole-house treatment requirements.
Radium Is Undetectable Without Testing — Test Before You Build
Related Reading
Well Water Testing Guide
Complete test panel for private well owners including radiological
How Reverse Osmosis Works
Why RO is effective against dissolved radioactive elements
Ion Exchange Technology
How water softeners remove radium as a byproduct of softening
Best Whole-House Water Filters
Whole-house systems for households needing multi-tap radium treatment
Well Water Complete Guide
Full treatment stack for private well owners
Arsenic in Water Guide
Another naturally-occurring geogenic contaminant common in well water