We pulled the contaminant profile for all 15 public water systems serving Mobile and Baldwin County and sorted by how many systems each substance appears in.
One thing appears in every single one.
Radium, 15 out of 15
Combined radium — radium-226 plus radium-228 — is detected above the Environmental Working Group's health guideline in every public water system in both counties. Not most. All of them.
That is unusual. Disinfection by-products come next at 14 and 13 systems, and those are a consequence of treatment, so their spread makes sense. Radium is not something anyone added.
Where it comes from
Radium is naturally occurring. It is a decay product of uranium and thorium in rock and sediment, and groundwater dissolves trace amounts as it moves through the formation. On the Gulf Coast, where most of these systems draw from sand and gravel aquifers, that contact is constant.
Nothing was spilled. No one is at fault. It is a property of the geology, which is exactly why it shows up everywhere at once instead of at one unlucky utility.
The numbers, and the two standards
Here is where it gets worth understanding rather than worrying about.
Federal legal limit: 5 pCi/L. That is the EPA's enforceable Maximum Contaminant Level for combined radium.
Local readings: 0.29 to 2.53 pCi/L, median 0.53. The highest reading in the two counties — Riviera Utilities at 2.53 — is roughly half the legal limit. Daphne Utilities is 2.05. Most systems sit well under 1.
EWG health guideline: 0.05 pCi/L. That is 100 times stricter than the legal limit, and it is not a law. It reflects a more conservative reading of long-term cancer risk than the enforceable standard does.
So every system here is comfortably legal and every system here exceeds the stricter guideline. Both statements are true, and which one you find meaningful is a judgement rather than a fact.
Why you have probably never heard about it
Two reasons.
Radium has no taste, no smell and no colour. Nothing about it announces itself at the tap, so it never generates the complaint that sends someone looking.
And it is boring in the specific sense that matters commercially: nobody is running ads about it, because the honest answer is "your water is legal and this is naturally occurring." That is a difficult thing to sell against, so it mostly goes unmentioned.
If you want to reduce it anyway
Some people will, and that is reasonable. The options, honestly ranked:
Reverse osmosis is the thorough answer for drinking water, and under-sink is where it belongs — treating every gallon in the house to drinking standard when you drink a fraction of a percent of it is wasteful.
Ion exchange — a conventional water softener — does reduce radium as a side effect, because radium behaves chemically much like calcium and magnesium and gets swapped out on the same resin. That is a real bonus, not a reason to buy one on its own.
Carbon filtration does not remove it. If a carbon system is being sold to you on a radium argument, that argument is wrong.
The honest summary
Every water system serving these two counties has detectable radium, all of it naturally occurring, all of it inside the federal limit, and all of it above a stricter voluntary guideline. That is the complete picture, and it does not resolve into a simple "safe" or "unsafe."
You can see the full contaminant profile and compliance record for your own system, including its actual radium reading, or have your own tap read rather than a system-wide average.
Contaminant profiles from the EWG Tap Water Database for each system's PWSID; federal limits from EPA's National Primary Drinking Water Regulations. Figures current as of 19 August 2026. A system-wide profile describes the distribution network, not a specific address.