Radium is a naturally occurring radioactive element that erodes from underground rock into groundwater. It is measured as the combined activity of radium-226 and radium-228.
In Florida, Combined Radium (226 + 228) was reported by 10 community water systems serving about 843,006 people. Every reported reading was at or below the federal legal limit. It was measured by 1,559 systems in all, so it was detected in 1% of the systems that tested for it.
The highest reading relative to the limit was at City of Arcadia in DeSoto County, at 91% of it.
Where it comes from: Erosion of natural deposits.
Enforceable. A utility must stay at or under this.
Health-based, not enforceable. Often lower than the limit, sometimes zero.
California OEHHA PHG for Radium-226 (2006)
Health effects the EPA associates with it: May increase the risk of cancer.
Water at or under the legal limit meets federal safety standards. A reading above a health goal is not the same as being unsafe, and health goals are set purely on health without regard to cost or treatability. Both are shown so the margin is visible either way.
These figures describe water as delivered by each utility, not what your home’s plumbing adds after it arrives. Informational; not a substitute for testing your own tap.