Radium (226 + 228) in Tap Water
Radium is a naturally occurring radioactive element that dissolves into groundwater from rock and soil. It is regulated as the combined activity of radium-226 and radium-228.
Natural radioactive decay of uranium and thorium in rock, dissolving into groundwater.
- 1Natural mineral deposits (granite, shale aquifers)
A result is read with its context
This radionuclide is tracked through federal and state compliance monitoring, measured as picocuries per liter (pCi/L). Private wells in affected geology should be tested directly. PurityMap does not yet publish a per-system measured value for Radium (226 + 228); this page is a reference explainer. To learn what is in your own water, check your utility’s Consumer Confidence Report (CCR) or use a certified home test.
- Above reference
- Evidence exceeds a reference level.
- Detected
- This substance was found in the monitoring record. Being present is not the same as being above a reference level, and this signal does not say which.
- Not detected
- Somebody looked and the laboratory reported nothing above its reporting limit. This is a result, and it is not the same as nobody looking.
- Not monitored
- No sampling for this substance has been reported for this system. Nothing is known either way, and an empty row is not a clean one.
22 cities with a health-based violation
A violation is a past event with a status, from the federal compliance record (EPA SDWIS, since 2016). It does not describe the water today.
- Gilbert Summit WdSouth CarolinaArchivedView city →
- Inver Grove HeightsMinnesotaArchivedView city →
- Michigan State UniversityMichiganResolvedView city →
- Western SpringsIllinoisResolvedView city →
- Box ElderSouth DakotaResolvedView city →
- FarmingtonMissouriResolvedView city →
- SavageMinnesotaArchivedView city →
- OttawaIllinoisResolvedView city →
- WaukeshaWisconsinResolvedView city →
- Perdido Bay FpdAlabamaResolvedView city →
- BountifulUtahResolvedView city →
- ElkhornWisconsinResolvedView city →
- MonumentColoradoResolvedView city →
- WinonaMinnesotaResolvedView city →
- BrookfieldWisconsinResolvedView city →
- South Saint PaulMinnesotaResolvedView city →
- BeloitWisconsinResolvedView city →
- Robeson CountyNorth CarolinaResolvedView city →
- SussexWisconsinResolvedView city →
- Manchester Twp - EasternNew JerseyResolvedView city →
- New BaltimoreVirginiaResolvedView city →
- OswegoIllinoisResolvedView city →
PurityMap does not yet publish a per-system measured value for radium (226 + 228). Check your utility’s Consumer Confidence Report, or use a certified home test.
What can carry a radium (226 + 228) reduction claim
- Reverse osmosis
Semi-permeable membrane separation removing dissolved minerals, heavy metals, and persistent fluorinated chemicals down to 0.0001 microns.
- Ion exchange (softening)
Dedicated whole-house appliance exchanging hardness ions (calcium and magnesium) for sodium or potassium to prevent scale buildup.
- Activated alumina
Boiling does not remove a dissolved chemical compound and can concentrate it. Many pitcher and refrigerator filters carry no verified claim for a compound like this at all.
A finding establishes the need, the need names the capability, the capability requires a verified certification. No product appears before that sequence completes. Filter Finder →
Frequently asked
Answers cite the same records as the page. How PurityMap analyzes water data
Radium is a naturally occurring radioactive element that dissolves into groundwater from rock and soil. It is regulated as the combined activity of radium-226 and radium-228.
The enforceable federal limit is 5 pCi/L combined radium-226 + 228 (MCL). The health-based goal (MCLG) is 0. PurityMap reads every measurement against its stated benchmark and never sets its own.
Natural mineral deposits (granite, shale aquifers).
Long-term exposure to radium above the limit increases cancer risk, particularly bone cancer, because radium behaves like calcium and deposits in bone. As with other radionuclides the health goal is zero and the enforceable limit is set near the lowest feasible level.
Treatment technologies commonly certified to reduce Radium (226 + 228) include Reverse osmosis, Ion exchange (softening), Activated alumina. Match the exact certified claim to your water before buying. Holding a format is not the same as holding the claim.
In the federal compliance record (EPA SDWIS, since 2016), 22 cities in PurityMap's record across 13 states had a water system measure Radium (226 + 228) above the legal limit, most recently in 2026, including Gilbert Summit Wd, SC; Inver Grove Heights, MN; Michigan State University, MI. Each violation is a past event with a published status, not a description of the water today.