Every time you fill a glass of water in parts of Illinois, Iowa, Wisconsin, or Minnesota, you might be pouring a tasteless, colorless radioactive element into your cup. Radium, a naturally occurring radioactive metal, seeps into deep groundwater supplies across America, and many homeowners have no idea it's there. Unlike lead pipes or chlorine that you might smell or taste, radium silently accumulates in your body over years of exposure, raising the risk of bone cancer and other health problems. This article explains what radium is, where it comes from, how much is too much, and what you can do to protect your family.
What is Radium and Why is It in Your Water?
Radium is a radioactive element that occurs naturally in the Earth's crust. It forms deep underground when uranium and other radioactive minerals slowly decay over millions of years. As water percolates through rock formations far below the surface, it dissolves radium and carries it into aquifers that supply drinking water wells.
This process is completely natural, but it becomes a public health concern when utilities pump water from deep wells where radium concentrations are high. The problem is especially severe in the Midwest and parts of Texas, where geological formations contain significant uranium deposits. Radium doesn't come from pollution or industrial waste, which is why it's often called a "naturally occurring contaminant." That label doesn't make it safe, but it does explain why radium contamination is difficult to prevent and why it affects both large municipal water systems and small private wells.
The Health Risks of Radium Exposure
Radium is a bone-seeker. When you ingest it through drinking water, your body treats it like calcium and deposits it in your bones and teeth. Once there, radium emits radiation that can damage bone cells and increase your risk of bone cancer and other cancers over time.
The risk from radium is cumulative and long-term. You won't get sick from one glass of water contaminated with radium, but drinking contaminated water for years or decades significantly raises your cancer risk. The EPA bases its safety limits on the concept of "lifetime exposure," meaning 70 years of daily consumption. People with the highest risk include:
- Children and teenagers, whose bones are still developing and absorb radium more readily
- Pregnant women, who pass radium to developing fetuses
- People who drink primarily tap water rather than bottled water
- Residents in areas with naturally high radium geology
The EPA classifies radium as a Group A carcinogen, meaning there is sufficient evidence it causes cancer in humans.
EPA Radium Standards and Maximum Contaminant Levels
In 1976, the EPA established the first federal drinking water standard for radium. The current standard, known as the combined radium MCL (Maximum Contaminant Level), is 5 picocuries per liter, or pCi/L. This limit applies to the combined concentration of radium-226 and radium-228, the two most common forms found in drinking water.
The 5 pCi/L standard is based on a 10-to-the-minus-4 cancer risk level, meaning the EPA considers this limit to pose no more than a 1-in-10,000 lifetime cancer risk from radium exposure alone. Water utilities are required to test for radium at least once every four years, though some states require more frequent testing.
If a utility's water supply exceeds 5 pCi/L, the utility must notify customers and take steps to reduce radium levels through treatment or by blending contaminated water with water from less-contaminated sources.
Which States and Regions Have the Highest Radium Contamination?
The Midwest Hotspots
Radium contamination is not evenly distributed across the United States. Certain geological regions have naturally high uranium content in bedrock and soil, which leads to elevated radium in groundwater. The Midwest is particularly affected.
Illinois has some of the highest radium levels in the nation. Many communities in central and northern Illinois rely on deep wells that draw water from sandstone and dolomite formations rich in uranium. Studies have found that a significant percentage of Illinois public water systems exceed or approach the EPA's 5 pCi/L limit. Small communities are often hit harder than large cities because they have fewer resources for treatment upgrades.
Iowa faces similar challenges. The state's reliance on groundwater, combined with geological formations in regions like the Missouri River valley, creates conditions where radium concentrations in some wells exceed federal standards. Rural areas and small municipalities report particularly high radium levels.
Wisconsin and Minnesota also report elevated radium in certain aquifers. The Upper Midwest's glacial geology and the presence of Precambrian rock formations mean that some utility wells, particularly in rural areas, pump water with radium above safe levels.
Texas, particularly in areas overlying the Llano Uplift geological formation in central Texas, also experiences naturally high radium in groundwater. Communities in this region have documented radium exceedances and have invested in treatment systems to bring water into compliance.
Why These Regions Are Affected
The common thread in all these high-radium states is geology. These regions have access to deep aquifers that contact ancient rock formations containing uranium. Wells that pump from depths of 500 feet or more are more likely to encounter radium than shallow wells. Additionally, the pH and mineral content of groundwater in these regions favor radium dissolution, making it more likely to remain suspended in water rather than settling out.
How to Check Your Water for Radium
For Municipal Water Customers
If you receive water from a public water utility, you have a right to know whether your water contains radium. Federal law requires utilities to provide a Consumer Confidence Report (CCR), also called a water quality report, to all customers at least once per year. This report lists all detected contaminants, including radium, and tells you whether your utility is in compliance with EPA standards.
To find your water quality report:
- Visit your local water utility's website and look for "Water Quality Report" or "Consumer Confidence Report"
- Call your utility's customer service line and request the most recent report
- Use ClearWater's free ZIP code lookup tool at checkclearwater.com to instantly access your utility's radium levels and compliance status
- Ask your utility directly about radium testing results and whether your water currently meets the EPA's 5 pCi/L standard
When you review the report, look specifically for radium-226, radium-228, or "combined radium" in the contaminant list. The report should show the level detected (in pCi/L) and whether it exceeds the MCL. If your utility reports "radium not detected" or a level below 5 pCi/L, your water is considered compliant. Levels at or above 5 pCi/L mean your utility is violating federal standards and is legally required to take corrective action.
For Private Well Users
If you have a private well, you are responsible for testing your own water. The EPA does not regulate private wells, though most states have guidance on well testing. To test for radium:
- Contact your state health department or environmental agency for a list of certified laboratories
- Hire a lab to collect a water sample from your well or collect it yourself following the lab's instructions
- Expect to pay $150 to $400 for a radium test, depending on whether you test for radium-226 and radium-228 separately or combined
- Get results within 2-4 weeks and review them against the EPA's 5 pCi/L standard
Private well owners in high-risk states (Illinois, Iowa, Wisconsin, Minnesota, and central Texas) should strongly consider radium testing, especially if the well is deep (500+ feet) or if neighboring wells have tested positive for radium.
What Utilities Are Doing to Reduce Radium
Water Treatment Methods
Water utilities use several proven technologies to remove radium from drinking water before it reaches your tap.
Ion exchange is one of the most common and effective methods. In this process, water passes through a resin bed that chemically exchanges radium ions for sodium or other harmless ions. The radium is removed, and the resin is later regenerated or disposed of as radioactive waste. Ion exchange can reduce radium by 85-95 percent.
Reverse osmosis forces water through a semi-permeable membrane that blocks radium and other contaminants. It is highly effective but produces wastewater and is typically used in smaller treatment plants or for point-of-use systems rather than at the utility-wide scale.
Barium sulfate precipitation involves adding barium sulfate to water, which chemically binds with radium and forms a solid that can be filtered out. This method is less common but is sometimes used in combination with other approaches.
Water blending is a simpler approach where a utility mixes high-radium water from one well with low-radium water from another well to bring the combined radium level below 5 pCi/L. This works for utilities with multiple sources but doesn't actually remove radium, only dilutes it.
Many utilities in the affected Midwest states have upgraded treatment infrastructure in the last decade. However, small utilities and rural water systems often struggle with the cost and technical expertise required to maintain these systems.
What You Can Do to Protect Your Family
Know Your Water Status
Your first step is to find out whether radium is present in your water and at what level. Use checkclearwater.com to look up your utility's most recent test results by ZIP code. If you have a private well, schedule a radium test through a certified lab. Don't delay on this, especially if you live in a high-risk state or have young children.
If Your Water Exceeds EPA Standards
If your utility's water tests above 5 pCi/L, contact your water utility and demand to know what remediation timeline they have committed to. Ask whether they have filed a compliance plan with the state and when treatment will be in place. Your state's health department or environmental agency can also help you file a complaint or request an inspection if the utility is not taking action.
Consider Point-of-Use Treatment
While your utility works on a utility-wide solution, you can install a home water treatment system to reduce your and your family's radium exposure. Point-of-use systems like reverse osmosis under-sink filters or whole-house ion exchange systems can remove 85-95 percent of radium. These systems require professional installation and ongoing maintenance, but they provide direct protection for your household.
Reduce Tap Water Consumption When Levels Are High
If your water has tested above the EPA standard and treatment is not yet in place, consider using bottled water for drinking and cooking until the situation is resolved. This is especially important for children, pregnant women, and nursing mothers, whose bodies absorb radium more readily.
Advocate for Compliance
If your utility is out of compliance, consider joining or organizing community pressure on local officials and the water utility. Compliance with radium standards may require investment in treatment infrastructure, but utilities are legally obligated to provide safe drinking water. Community advocacy has been effective in pushing utilities to upgrade treatment systems.
Frequently Asked Questions About Radium in Tap Water
Can I taste or smell radium in my water?
No. Radium is tasteless, odorless, and colorless. This is why testing is the only way to know whether it's present.
Is boiling water effective in removing radium?
No. Boiling water does not remove radium and may actually concentrate it by reducing the volume of water while the radium remains.
How long does radium stay in your body?
Radium is slowly eliminated from the body through urine and feces, but some can remain in bone tissue for years. The longer you are exposed to radium in drinking water, the more builds up in your skeleton.
Is my risk significant if my water is just slightly above the EPA standard?
The EPA standard of 5 pCi/L is designed to limit cancer risk to 1 in 10,000 over a lifetime. Water above this level poses an increased cancer risk. Even small exceedances are not safe, and you should advocate for compliance and consider treatment options.
Are there states where radium is not a concern?
Radium is found in groundwater nationwide, but concentrations are typically much lower in states with younger geological formations and different hydrogeology. Coastal states and areas with surface water supplies face radium issues less frequently than the Midwest.
Take Action Today
Radium in tap water is a real health risk, but it is measurable and, in most cases, treatable. The first step is knowing whether your water is affected. If you live in Illinois, Iowa, Wisconsin, Minnesota, Texas, or other states where radium is common, don't wait for symptoms. Check your water quality today using ClearWater's free ZIP code lookup. If you find elevated radium, contact your utility, consider treatment options, and advocate for compliance. Your family's long-term health depends on taking action now.