Groundwater in Hennepin County contains manganese, iron, and PFOA along with several other contaminants that exceed EPA health standards, including arsenic, lead, nitrate, uranium, and additional PFAS chemicals. These levels are concerning enough that well owners should test their water.
The rock beneath Hennepin County naturally releases iron and manganese as water moves slowly through it over time. Arsenic and uranium also occur naturally in these rock layers. PFAS chemicals like PFOA come from human sources--industrial sites, firefighting foam at airports and military bases, and some consumer products--and have contaminated groundwater in parts of the county. Road salt and agricultural nitrate add to the mix from land use above.
Groundwater in Hennepin County is very hard, driven by elevated calcium and magnesium from the minerals in the rock. The high iron concentration adds a metallic character to the water quality. These mineral and metal characteristics are widespread across wells throughout the county.
Wells in Hennepin County contain several contaminants that exceed EPA health standards. Arsenic, lead, uranium, and radium increase cancer risk and damage organs. Nitrate is especially dangerous for infants and can affect oxygen in the blood. PFOA, PFOS, PFHXS, and PFNA are human-made chemicals that build up in your body over time. Manganese at these levels can harm brain development and nervous system function.
The water in this county is extremely hard, which causes visible problems in your home. You will see rust and orange stains on fixtures, clothes, and surfaces from iron. Scale builds up inside pipes and water heaters, shortening their lifespan significantly. Hard water also makes soap less effective and can leave residue on skin and hair. The combination of hardness and minerals affects how appliances like dishwashers perform.
Testing your well is the only way to know what contaminants are actually in your water, since every well is different. Your well may have higher or lower levels than what is common in the county. We recommend a comprehensive metals and minerals panel, which typically costs $200-400 and tests for all major concerns. Water softeners, iron filters, and activated carbon treatment can address these issues once you know your specific levels.
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 ⓘ |
|---|---|---|---|---|---|
| Manganese | 834 | 80% | High | High | |
| Iron | 926 | 52% | High | High | |
| PFOA ⓘ municipal | 322 | 38% | High | High | |
| PFOS ⓘ municipal | 293 | 31% | High | High | |
| Chloride | 1047 | 16% | High | High | |
| PFHxS ⓘ municipal | 199 | 13% | High | Moderate | |
| Arsenic | 560 | 7% | High | Moderate | |
| Sulfate | 870 | 4% | High |
Moderate
Elevated concentration, not % above limit
|
|
| Uranium | 92 | 3% | Moderate |
Moderate
Elevated concentration, not % above limit
|
|
| Nitrate | 446 | 2% | High | Low | |
| Lead | 653 | 2% | High | Low | |
| PFNA ⓘ municipal | 227 | 0% | High | Low | |
| Fluoride | 526 | 0% | High | Low | |
| Nitrite | 297 | 0% | High | Low | |
| Radon | 19 | 0% | Moderate | Low ⓘ | |
| HFPO-DA (GenX) ⓘ municipal | 190 | 0% | High | Safe | |
| Sodium | 840 | — | High | Low | |
| pH | 457 | — | High | Low | |
| PFBS ⓘ municipal | 208 | — | High | Low | |
| Hardness | 398 | — | 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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