Groundwater in Cook County contains iron, manganese, lead, and chloride at levels that exceed EPA health standards. These contaminant levels are concerning and warrant your attention.
The rock beneath Cook County naturally contains iron and manganese minerals that dissolve into groundwater as water moves slowly through cracks and spaces in the stone. Lead enters the water from the bedrock itself. Chloride appears in smaller amounts, partly from road salt and natural mineral sources in the rock.
Groundwater in Cook County is moderately hard, driven by elevated iron and manganese from the local bedrock. As water seeps through these iron-bearing rocks over time, these metals concentrate in the water supply. Elevated iron and manganese are common across wells in this county.
Wells in Cook County commonly contain iron, lead, manganese, and chloride at levels that exceed EPA health standards. Iron and manganese can damage your blood and organs with long-term exposure. Lead is especially dangerous because it harms brain development in children and can affect nervous system function in adults. Chloride at elevated levels can be a concern for people on restricted salt diets.
Hard water in this county can cause rust-colored or orange stains on sinks, toilets, and laundry. Iron may also create a metallic taste in your water. Over time, the moderately hard water can shorten the lifespan of water heaters and dishwashers by building up scale inside the pipes and equipment.
We recommend testing your well with a comprehensive metals and minerals panel to find out exactly what is in your water. Every well is different, and your well may have higher or lower levels than what is common in the county. Testing is the only way to know what needs to be treated. A comprehensive panel typically costs between two hundred and four hundred dollars, and iron and manganese removal systems 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 ⓘ |
|---|---|---|---|---|---|
| Iron | 23 | 61% | Moderate | High | |
| Manganese | 23 | 39% | Moderate | High | |
| Lead | 8 | 25% | Low | High ⓘ | |
| Chloride | 23 | 4% | Moderate |
Moderate
Elevated concentration, not % above limit
|
|
| Fluoride | 23 | 0% | Moderate | Low | |
| Arsenic | 10 | 0% | Low | Low | |
| Nitrate | 23 | 0% | Moderate | Low | |
| Nitrite | 15 | 0% | Moderate | Low | |
| PFNA | 2 | 0% | Low | Safe ⓘ | |
| PFOA | 2 | 0% | Low | Safe ⓘ | |
| Sulfate | 23 | 0% | Moderate | Low | |
| Hardness | 15 | — | Moderate | Low | |
| Sodium | 23 | — | Moderate | Low | |
| pH | 15 | — | 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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