Radium Is in More NJ Private Wells Than Most Homeowners Realize — and It’s One of the Few Contaminants Where the Health Risk Is Real at Concentrations You Can’t See, Smell, or Taste.
Radium is a naturally occurring radioactive element that dissolves from uranium-bearing rock into groundwater across significant portions of New Jersey. It has no color, no odor, no taste, and produces no symptoms at residential exposure levels — which means the only way to know it’s in your well water is to test for it. Jersey Radon’s licensed water testing team includes radium in comprehensive well water assessments for homes in northern and central NJ, where the geology creates documented radionuclide risk in private wells. Here’s what radium is, why it matters for NJ homeowners, and what treatment actually removes it.
What Is Radium and How Does It Get Into NJ Well Water?
Radium is a radioactive metal that forms naturally in the environment as uranium decays through a series of intermediate elements. The same uranium-bearing bedrock geology of New Jersey’s Highlands and Reading Prong region that drives elevated radon gas levels in homes also produces dissolved radium in groundwater. As water percolates through granite, gneiss, and other uranium-rich formations, it dissolves small amounts of radium from the surrounding rock. Because private wells draw directly from this groundwater without treatment, whatever radium is present in the aquifer reaches the tap without any reduction. According to the EPA’s Radionuclides Rule, the maximum contaminant level (MCL) for combined radium-226 and radium-228 in drinking water is 5 picocuries per liter (pCi/L) — an enforceable federal standard for public water systems that private well owners in New Jersey must achieve through their own testing and treatment.
Two isotopes of radium are regulated in drinking water: radium-226 and radium-228. Both are decay products of uranium — radium-226 from uranium-238, and radium-228 from thorium-232, which is itself a decay product of uranium-238. In NJ private wells, both isotopes can be present simultaneously, and the regulatory standard applies to their combined activity. A well with radium-226 at 3 pCi/L and radium-228 at 3 pCi/L has a combined activity of 6 pCi/L — above the MCL even though neither isotope individually exceeds a single threshold. New Jersey’s PWTA requires radium testing as a primary parameter at every residential real estate transaction involving a private well, making it one of the contaminants that most buyers will receive a result for at closing. The question is whether they understand what that result means.
Is Radium in NJ Well Water a Common Problem?
Radium in private wells is not universal in New Jersey, but it is documented and geographically predictable. The highest-risk areas are in the northern counties overlying the Highlands and Reading Prong formations — Hunterdon, Morris, Warren, Sussex, and Somerset counties — where granite and metamorphic bedrock contains naturally elevated uranium concentrations. Wells in these areas drilled into bedrock fractures that pass through uranium-bearing formations are at higher risk than wells in the sandstone or shale units of the Piedmont or the sandy aquifers of the Coastal Plain. The correlation between elevated radon and elevated radium in the same wells is well established — both derive from the same parent uranium geology. If your home has documented high air radon from geological sources and you’re on a private well, testing specifically for radium-226 and radium-228 is warranted regardless of whether the PWTA test has been recently completed.
What Health Risks Does Radium in Drinking Water Present?
Radium is a known human carcinogen. Unlike many water contaminants where the health risk is associated with acute exposure at high concentrations, radium’s health risk derives from chronic, long-term exposure at concentrations that fall in the range found in residential wells. Radium is chemically similar to calcium — the body incorporates it into bone tissue, where it emits alpha radiation at close range over time. Long-term exposure above the MCL has been associated with increased risk of bone cancer and leukemia. The EPA’s maximum contaminant level of 5 pCi/L was established specifically to limit lifetime cancer risk from radium ingestion to an acceptable level for a population drinking the water daily over decades.
The health concern for radium is not about what you feel — it is about what accumulates. A household drinking well water with radium at 8 pCi/L for five years is receiving a meaningful cumulative radiation dose that wouldn’t be occurring with treated water. Children are at greater risk than adults from radium exposure because bone is actively growing and incorporating minerals — including radium — at higher rates during childhood development. Households with children on private wells in high-radium geological areas have a stronger practical reason to test and treat than the regulatory framework alone conveys.
Is Radium Different from Radon in Well Water?
Yes — and the distinction matters for understanding both the source and the treatment. Radon in well water is a dissolved gas — it volatilizes out of water into indoor air when water is used, primarily during showering. Radium is a dissolved metal — it doesn’t volatilize and stays in the water as you drink it. The health pathways are different: water radon exposure is primarily through inhalation of radon gas released from water into the home; radium exposure is primarily through ingestion. Both derive from the same uranium geology, and elevated radium in a well should prompt testing for radon in both air and water if those tests haven’t been done recently. Our page on radon in NJ well water covers the water radon situation, which is a separate measurement and a separate treatment system from radium.
A private well can have elevated radon in water without elevated radium, or elevated radium without elevated water radon, depending on the specific geology and hydrogeology of the aquifer. They should be tested separately. A PWTA test that includes water radon does not include radium by default — radium is a different analytical parameter that must be separately reported as a primary parameter on the PWTA panel.
- Radium-226 and radium-228 are both PWTA primary parameters — reported at every NJ real estate transaction well test
- MCL is 5 pCi/L combined — both isotopes count toward the limit together
- Highest risk areas: Hunterdon, Morris, Warren, Sussex, Somerset counties overlying Highlands and Reading Prong bedrock
- No color, odor, or taste — completely undetectable without a laboratory test
- Health risk is cumulative over years of exposure — not from a single glass of water
- Radium and radon in water are separate contaminants requiring separate tests and separate treatment
What Treatment Options Remove Radium from NJ Well Water?
Radium removal is achievable through several treatment technologies, each with different tradeoffs in cost, complexity, and performance. The right approach depends on the radium concentration, what other parameters are present in the water, and the household’s needs. Unlike many aesthetic contaminants where treatment is optional, radium above the MCL represents a genuine health-based reason to treat — and the treatment technologies available for residential systems are well proven.
Cation exchange water softeners are one of the most practical radium treatment options for residential NJ wells, because radium is chemically similar to calcium and magnesium — the minerals that standard ion exchange softeners already remove. A properly functioning water softener that regenerates on schedule removes a significant percentage of dissolved radium-226 and radium-228 alongside hardness minerals. In many NJ homes where both hard water and elevated radium are present — a common combination in the northern county bedrock well systems — a water softener addresses both conditions simultaneously. The limitation is that softeners don’t reduce radium to near-zero levels — they typically achieve 70 to 90% reduction, which may or may not bring levels below the MCL depending on the starting concentration. Our water softener installation page covers how we size and specify softeners for NJ well conditions.
Does Reverse Osmosis Remove Radium?
Yes — reverse osmosis is highly effective for radium removal, achieving reductions of 90 to 99% at the point of use. An under-sink RO system installed at the kitchen tap produces water with radium levels well below the MCL, providing protection specifically for drinking and cooking water where ingestion risk is concentrated. The limitation of point-of-use RO is that it doesn’t treat water used for bathing — but ingestion is the primary radium exposure pathway, so a well-maintained RO system at the kitchen tap addresses the most significant route of concern. For households where radium levels are substantially above the MCL and whole-house treatment is desired, a combination of water softening for whole-house radium reduction and point-of-use RO for drinking water is a common and effective approach.
Are There Other Treatment Options for Radium?
Activated alumina and modified anion exchange resins specifically designed for radionuclide removal are available as whole-house treatment options, though they are less commonly installed in residential applications than softeners or RO. These systems can achieve high radium removal rates and don’t require the salt regeneration that softeners need, which makes them appealing in applications where adding sodium to the water supply is a concern. Radium-specific treatment should always be evaluated alongside a full water chemistry panel — because radium co-occurs with other parameters (hardness, iron, pH) that influence both treatment effectiveness and system design. A treatment system specified without understanding the complete water chemistry may remove radium while underperforming on another parameter, or may be designed in a sequence that limits its effectiveness.
| Treatment Technology | Radium Removal Effectiveness | Notes for NJ Well Systems |
|---|---|---|
| Ion exchange water softener | 70–90% reduction | Addresses radium and hardness simultaneously; common in northern NJ; may not achieve MCL if starting concentration is high |
| Point-of-use reverse osmosis | 90–99% reduction | Best for drinking/cooking water protection; doesn’t treat whole-house supply; excellent for ingestion pathway |
| Activated alumina | High — depends on pH and co-contaminants | Less commonly installed residentially; effective alternative when sodium addition is a concern |
| Sediment or carbon filters | Negligible | Not designed for dissolved radionuclides; do not treat radium |
| UV disinfection | None | UV treats biological contamination only; has no effect on dissolved radioactive metals |
What Do NJ Home Buyers Need to Know About Radium in Well Water?
Because radium is a PWTA primary parameter, buyers purchasing a home with a private well in New Jersey will receive radium-226 and radium-228 results as part of the closing water test. A combined radium result above 5 pCi/L is a flagged primary parameter failure — not a secondary aesthetic recommendation — and it warrants a treatment response, not a monitoring approach. Buyers who receive a flagged radium result should request cost estimates for treatment before closing and either negotiate a credit or require the seller to install a remediation system. A well water result above the MCL for radium is the same regulatory status as a result above the MCL for arsenic or nitrates — it’s a primary health-based limit, not a guideline.
If a home already has a water softener and the radium result is at or just below the MCL, verify that the softener is functioning properly and regenerating on schedule. A softener that’s salt-bridged, fouled with iron, or past its service life may not be providing the radium reduction it was designed for — and the test result may reflect water from a softener that was bypassed or non-functional at the time of sample collection. Our guide to private well water testing in New Jersey covers how to interpret PWTA results and what buyers should evaluate beyond the minimum required panel.
Getting Radium Testing and Treatment Right for Your NJ Well
Radium in NJ well water is one of the most important contaminants to understand clearly — because it has a real health basis for treatment, it’s geographically predictable in northern NJ, and the treatment options are well established. Jersey Radon’s licensed water treatment team evaluates radium results in the context of the full water chemistry panel and recommends treatment approaches matched to the actual radium concentration and co-occurring conditions in each specific well. We serve residential homeowners and home buyers throughout New Jersey, including the northern county communities where geological risk for radium is highest.
If your PWTA result showed elevated radium, or you’re in a northern NJ county on a private well and haven’t recently tested specifically for radionuclides, contact us for a free estimate — we serve all of New Jersey and are available any time.
