If your home in Lake St. Louis gets its water from a private well, radium is one of the contaminants worth testing for, even when the nearby city supply looks fine. Radium is a naturally occurring element found in some bedrock aquifers in eastern Missouri. It does not show up by taste, smell, or color, so a lab test is the only way to know what your well contains.
What radium is and where it comes from
Radium forms over time as uranium and thorium break down in rock. Deep bedrock aquifers can carry it into groundwater, and wells that reach those layers are the ones most likely to show it. Shallow wells in river-bottom soil often have different problems, such as iron or manganese staining, so the depth and geology of your well matter when deciding what to test.
Why it comes up in this area
The Lake St. Louis service area sits near the former Weldon Spring cleanup site. Public water reports for the municipal supply describe radium readings as within limits, and that is a good reason to keep the municipal results in context. Those readings describe the city system, not your private well. Your well draws from its own source, so it needs its own test.
Who should test
- Owners of private wells, especially those drawing from deep bedrock
- Buyers considering a home with a well that has no recent radium result
- Anyone whose well has not been tested for this contaminant in a long time
- Anyone who has changed the well, the pump, or the treatment equipment
How to order and collect the sample
- Choose a laboratory certified by your state environmental agency, and ask for the radium panel by name.
- Collect the sample from an untreated tap, ideally before the water reaches any softener, filter, or other equipment. Treatment changes the water, so a sample taken after treatment does not describe the source.
- Follow the lab's bottle, preservative, and cold storage instructions exactly.
- Write down the date, the time, and the tap you used, and return the sample to the lab promptly.
Reading the report
A radium report typically lists a measured result, a limit it is compared against, and an uncertainty figure that shows how precise the measurement is. Read the limit, not just the result. A value below the limit tells you the sample met that standard on the day it was collected. A value near the limit, or one with a wide uncertainty range, is a reason to ask the lab or a water professional about retesting before you decide anything.
Keep in mind that the report describes one sample from one tap on one day. Ask the lab whether the result applies to the whole well or only to the tap you sampled.
What to do with the results
Do not assume a softener addresses radium. A softener is designed around hardness, and radium treatment depends on the specific results and the specific equipment. Before you buy anything, ask a licensed water professional or your local health agency to explain what the results mean for your home. Ask them which treatment, if any, fits your well and how often to retest. Get that advice in writing if you can, so you have a record to compare against future tests.
Keeping records
- Save every lab report in one folder, paper or digital.
- Note any changes to the well, pump, pressure tank, or treatment equipment.
- Add the next radium test to your yearly testing calendar, so it does not slip.
Radium testing in Lake St. Louis is a straightforward process once you know the steps. Collect an untreated sample, read the limit as well as the result, and get local guidance before choosing equipment. A clear report and a dated record will make every future decision easier.