Groundwater in St. Louis County contains manganese, radon, and PFOS, along with iron, PFHXS, PFNA, PFOA, and sulfate at levels that exceed EPA health standards. These contaminants are present at concentrations the EPA considers concerning enough to warrant action.
Manganese and iron dissolve naturally from the rock layers that hold water in this area. Radon comes from radioactive decay deep in the rock and soil. PFOS and related chemicals enter groundwater from industrial sources and some types of firefighting foam or non-stick coatings that have contaminated surface areas. Sulfate also occurs naturally in the local geology and builds up in groundwater over time.
Groundwater in this county is soft with moderate iron as the main mineral characteristic. Iron concentrates in these water-bearing rock layers because the rock contains iron-rich minerals that release iron as water flows through them. Moderate iron levels are widespread across wells in St. Louis County.
Wells in St. Louis County contain several contaminants that exceed EPA health standards. Iron and manganese can damage organs and affect how your body uses nutrients, especially in children and pregnant women. Radon is a radioactive gas that increases the risk of lung cancer over time. PFOA, PFOS, PFNA, and PFHXS are "forever chemicals" linked to liver damage, thyroid problems, and cancer. Sulfate at elevated levels can cause digestive issues.
The iron in county wells can stain your laundry, dishes, and bathroom fixtures with brown or orange marks. It can also create an unpleasant metallic taste. Since the water here is relatively soft, you won't deal with heavy scale buildup on pipes and appliances like people in harder water areas do.
We recommend having your well tested with a comprehensive panel covering metals, minerals, and contaminants. Testing costs $200-400 and is the only way to know what is actually in your water. Your well's contamination levels could be higher or lower than the county average, so testing is essential before deciding on treatment. Iron and radon removal systems, along with activated carbon filters for chemical contaminants, can address many of these concerns.
Not sure if your well is affected? Get certified results in 5–7 days.
Test Your Well Water with Tap Score →| Contaminant | Samples ⓘ | % Above MCL ⓘ | Distribution ⓘ | Confidence ⓘ | Risk ⓘ |
|---|---|---|---|---|---|
| Radon | 1 | 100% | Low | High ⓘ | |
| Manganese | 504 | 57% | High | High | |
| PFOA ⓘ municipal | 169 | 48% | High | High | |
| PFOS ⓘ municipal | 150 | 43% | High | High | |
| Iron | 519 | 31% | High | High | |
| PFHxS ⓘ municipal | 80 | 26% | Moderate | High | |
| Chloride | 588 | 6% | High | Moderate | |
| Arsenic | 419 | 5% | High | Moderate | |
| Lead | 440 | 3% | High |
Moderate
Elevated concentration, not % above limit
|
|
| Sulfate | 523 | 1% | High | Low | |
| Fluoride | 445 | 0% | High | Low | |
| HFPO-DA (GenX) ⓘ municipal | 54 | 0% | Moderate | Safe | |
| Nitrate | 83 | 0% | Moderate | Low | |
| Nitrite | 23 | 0% | Moderate | Low | |
| PFNA ⓘ municipal | 80 | 0% | Moderate | Low | |
| Uranium | 1 | 0% | Low | Low ⓘ | |
| Hardness | 192 | — | High | Low | |
| PFBS ⓘ municipal | 62 | — | Moderate | Low | |
| pH | 158 | — | High | Low | |
| Sodium | 544 | — | High | Low |
MCL = Maximum Contaminant Level (EPA limit for public water; used as benchmark for private wells). Distribution shows % of sampled wells in each concentration band. Methodology.
* Microbial contaminants (E. coli, coliform) reflect only samples from the last 10 years.
Data shows potential risk — a certified test confirms whether your water is affected.
Order a Tap Score Test →Population-level CDC data. Not individual risk prediction.
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