Groundwater in Rock County contains manganese, iron, arsenic, lead, nitrate, sulfate, and PFOA. Several of these contaminants exceed EPA health standards, with iron reaching very high levels and hardness at very hard levels, making this water a concern for well owners.
The rock layers beneath this county naturally contain iron and manganese, which dissolve into groundwater over time. Arsenic and lead also occur naturally in the bedrock. Nitrate comes from agricultural fertilizers and animal manure seeping down through the soil. Sulfate enters the water from both natural rock dissolution and human sources. PFOA is an industrial chemical that has contaminated some wells through past manufacturing or disposal practices.
Groundwater in this county is very hard, driven by elevated calcium and magnesium from the surrounding rock, along with very high iron and moderate sulfate concentrations. These minerals build up in water as it moves slowly through the bedrock and soil layers. Most wells in Rock County show these hard-water and elevated-iron characteristics, though the exact levels vary from well to well.
Wells in Rock County commonly have arsenic, lead, manganese, nitrate, and PFOA at levels above EPA health standards, along with elevated iron and sulfate. Arsenic can harm your kidneys and increase cancer risk over time. Lead is especially dangerous for children because it can damage brain development and learning. Manganese at high levels can affect the nervous system. Nitrate is risky for infants and can reduce how well blood carries oxygen. PFOA is a chemical linked to health problems with the liver, thyroid, and immune system.
The very hard water in this county will leave white crusty scale on faucets, shower heads, and inside pipes. You will notice spots on dishes and glassware after washing. Soap and shampoo work poorly in hard water, so you use more of them. The water may have a slightly earthy taste from the minerals. This extreme hardness also wears out water heaters, dishwashers, and washing machines faster than normal, shortening their lifespan.
We recommend a comprehensive water test because your well may have higher or lower levels than what is common here in the county. Testing is the only way to know what is actually in your water so you can treat it properly. A full metals and minerals panel typically costs between $200 and $400. Treatment options like reverse osmosis systems or whole-house filters can remove many of these contaminants.
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 | 100 | 63% | High | High | |
| Iron | 110 | 56% | High | High | |
| PFOA ⓘ municipal | 3 | 33% | Low | High ⓘ | |
| Sulfate | 155 | 16% | High | High | |
| Nitrate | 73 | 14% | Moderate | Moderate | |
| Arsenic | 54 | 7% | Moderate | Moderate | |
| Lead | 54 | 2% | Moderate | Low | |
| Chloride | 170 | 0% | High | Low | |
| Fluoride | 117 | 0% | High | Low | |
| HFPO-DA (GenX) ⓘ municipal | 1 | 0% | Low | Safe ⓘ | |
| Nitrite | 60 | 0% | Moderate | Low | |
| PFHxS ⓘ municipal | 1 | 0% | Low | Safe ⓘ | |
| PFNA ⓘ municipal | 1 | 0% | Low | Safe ⓘ | |
| PFOS ⓘ municipal | 4 | 0% | Low | Low ⓘ | |
| Hardness | 37 | — | Moderate | Low | |
| PFBS ⓘ municipal | 1 | — | Low | Safe ⓘ | |
| pH | 89 | — | Moderate | Low | |
| Sodium | 120 | — | 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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