If your home in O'Fallon gets its water from a private well, arsenic is one substance worth knowing about. Arsenic is a naturally occurring element that can dissolve into groundwater from surrounding rock and soil. It has no taste, color, or smell, so water that looks clear can still contain it. Testing is the only dependable way to learn what is in your own well water.
Why arsenic is on the list for local water
Local water reports for O'Fallon describe a mix of river water and groundwater as sources for area homes, and they list arsenic among the topics they cover. Public water systems are tested on a regular schedule. Private wells are not. As a well owner, you are responsible for testing your own water, so the public report for your city does not tell you what comes out of your own tap.
What to know before you test
- Your well type matters. Shallow wells and deep bedrock wells can carry different substances, so find out how deep yours is and check the drilling record if you have one.
- Arsenic is measured in a laboratory. Quick strips and drop-style home tests are not designed to give a reliable arsenic result.
- Look for a state-certified or accredited laboratory that lists arsenic among the drinking water tests it performs.
- Ask the lab for the correct sample bottle and follow its collection instructions exactly.
Collecting a sample
Lab instructions vary, so follow the ones that come with your bottle. Keep the bottle clean and closed until you fill it, and do not rinse it with anything other than what the lab specifies. Label the bottle with the date, the sampling location, and the tap used. Send it to the lab promptly so it arrives within the window the lab states.
Reading the results
A lab report lists any detected amount in a stated unit and compares it with a reference level. Keep the report with your well records. If a result is above the reference level, talk with a qualified water treatment professional or your local health office about next steps, and ask whether a retest is needed. Do not guess at a fix from a single result. Do not treat one clean result as permanent either, since well chemistry can change after flooding, well repairs, or nearby construction.
Where a softener fits in
A softener is built to remove hardness minerals such as calcium and magnesium. It is not designed to remove arsenic, so a softener on your line does not answer an arsenic question. Treatment for arsenic is a separate decision that depends on the form of arsenic present and the lab results. Keep that distinction clear when you discuss your water with anyone.
Practical next steps
- Find your well's depth and construction details.
- Order an arsenic test from a certified laboratory and collect the sample as directed.
- Store the report with your home records.
- If results are high, ask a qualified professional and your local health office what to do next.
- Schedule retesting with your lab or health office on a timeline you agree on.
Testing is a small, direct step that gives your household in O'Fallon a real answer about its water. Start there before deciding anything else about your water.