If your St. Peters home runs on a private well, a standard bacteria or hardness panel may not tell you everything about what is in the water. Two naturally occurring elements, radium and uranium, show up in parts of the region, and you cannot see, smell, or taste either one. This guide explains where they come from locally and how to test for them without guessing.
Where these elements come from
Radium and uranium occur naturally in some rock and soil. Over time, groundwater moving through those formations can pick them up. In St. Peters and the surrounding area, deeper aquifers are the main concern for radium, so a well drawing from depth should not be assumed safe just because the water looks clear.
Uranium has a different local story. Alluvial groundwater, the water held in river-deposited sand and gravel, has a documented uranium presence near the former Weldon Spring chemical and ordnance site. Whether a given well is affected depends on its depth, its aquifer, and its location, so a neighbor's result only goes so far. Your own well needs its own test.
What a standard panel may miss
Many routine well checks focus on bacteria, nitrate, or hardness. Those are useful, but they do not automatically include radium or uranium. Ask the lab directly and look for a radium test, often listed as combined radium, and a uranium test by name. A gross alpha screen can flag that something needs follow-up, but it does not identify which element is present, so treat it as a starting point rather than a final answer.
Steps for a St. Peters well owner
- Find your well record. Note the depth, the casing details, and the year it was drilled. The driller's log often shows which formation you draw from.
- Choose a state-certified laboratory that offers radium and uranium analysis. Confirm the lab can handle your sample type and holding time.
- Ask for the sample container and collection instructions before you go. Some labs supply preservative bottles, and using the wrong one can spoil the result.
- Collect the sample from a cold tap upstream of any treatment equipment, such as a softener or filter, so you see the source water.
- Keep the chain-of-custody form and the report together with your well records.
Reading the results
A report lists each element with a result and a reporting limit. Compare each result against the drinking water standard that applies to your situation, and ask the lab to explain anything you do not understand. If a result is above that standard, the next step is a conversation with a qualified water treatment professional and, if needed, your local health office. Do not treat a single result as the whole story. If you install any treatment yourself, retest after it is in service.
Between tests
Retest if your well is repaired, if the pump or casing is disturbed, or if nearby well construction changes. Keep a simple file with the date, lab, elements tested, and results. Over time, that file shows whether your water is steady or changing, which tells you more than any single report.
What this guide does not cover
This guide does not tell you whether your water is safe. It explains how radium and uranium arise in the region and how a St. Peters homeowner can test with confidence. Your results, not a map, should decide your next step.