Groundwater in Marquette County contains nitrate, arsenic, and chloride. Nitrate levels exceed the EPA health standard and should concern well owners, while arsenic and chloride are present but at lower levels.
Nitrate comes from fertilizers and animal waste on the land surface that seep down into the aquifer. Arsenic and chloride occur naturally in the bedrock layers beneath the county. The shallow to moderate depth of many wells in this area makes them more vulnerable to nitrate contamination from agricultural and residential sources above.
Groundwater in this county is very hard, driven by elevated calcium and magnesium from the limestone and rock layers below. As water passes slowly through these deep rock formations, it dissolves these minerals in significant amounts. Very hard water is widespread across wells throughout Marquette County.
Nitrate is found at levels exceeding EPA health standards in wells across Marquette County. Drinking water with elevated nitrate is especially risky for infants and can interfere with how blood carries oxygen through the body. Adults exposed over time may also experience health effects. Testing your well is the only way to know if nitrate is a concern in your specific situation.
Marquette County wells are very hard, which means scale buildup will form inside pipes, water heaters, and dishwashers. This extreme hardness can shorten the lifespan of appliances. You may also notice that soap doesn't lather well and that hard-water spots appear on dishes and fixtures. Bathing and laundry may feel less clean than you'd like.
We recommend testing your well water, since every well is different and yours may have higher or lower levels than what's common in the county. A basic screening for bacteria and nitrate runs $50-100 and gives you a clear starting point. Testing is the only way to know what's actually in your water so it can be properly treated. Water softeners can reduce hardness, and nitrate removal systems are available if needed.
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 ⓘ |
|---|---|---|---|---|---|
| Nitrate | 42 | 33% | Moderate | High | |
| Arsenic | 23 | 0% | Moderate | Low | |
| Chloride | 43 | 0% | Moderate | Low | |
| Fluoride | 43 | 0% | Moderate | Low | |
| HFPO-DA (GenX) | 3 | 0% | Low | Safe ⓘ | |
| Iron | 43 | 0% | Moderate | Low | |
| Lead | 25 | 0% | Moderate | Low | |
| Manganese | 43 | 0% | Moderate | Low | |
| Nitrite | 40 | 0% | Moderate | Low | |
| PFHxS | 3 | 0% | Low | Safe ⓘ | |
| PFNA | 3 | 0% | Low | Safe ⓘ | |
| PFOA | 3 | 0% | Low | Low ⓘ | |
| PFOS | 3 | 0% | Low | Safe ⓘ | |
| Radon | 5 | 0% | Low | Low ⓘ | |
| Sulfate | 43 | 0% | Moderate | Low | |
| Uranium | 28 | 0% | Moderate | Low | |
| Hardness | 43 | — | Moderate | Low | |
| PFBS | 3 | — | Low | Low ⓘ | |
| pH | 45 | — | Moderate | Low | |
| Sodium | 43 | — | Moderate | 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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