Groundwater in Ozaukee County contains lead, arsenic, sulfate, chloride, iron, and PFOA/PFOS compounds that well owners should be aware of. Several of these contaminants exceed EPA health standards and warrant attention.
These contaminants come from two sources. The bedrock beneath the county naturally releases iron, sulfate, and arsenic as groundwater moves slowly through it. Lead and the PFOA/PFOS compounds enter from human sources--old plumbing, industrial activity, and contaminated sites on the surface that leak downward into the water supply.
Groundwater in this county is very hard, driven by elevated calcium and magnesium from the limestone and dolomite rock below. The rock dissolves slowly as water passes through it, releasing these minerals into the water. Very hard water is common across wells throughout Ozaukee County.
Wells in Ozaukee County commonly contain chloride, sulfate, iron, arsenic, lead, and PFOA and PFOS at levels above EPA health standards. Arsenic and lead can cause serious health problems over time, including increased cancer risk and damage to the nervous system and kidneys. PFOA and PFOS are industrial chemicals that build up in your body and can affect your immune system, liver, and thyroid. Chloride at high levels can raise blood pressure in people who are sensitive to salt.
Ozaukee County's groundwater is extremely hard, which causes white crusty buildup on faucets, pipes, and inside appliances. You may see orange or brown staining in sinks and toilets from iron. The water may taste salty or bitter from the high mineral content. This extreme hardness can shorten the lifespan of water heaters, dishwashers, and washing machines.
We recommend a comprehensive metals and minerals panel to find out what is actually in your well, since every well is different and yours 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 full panel typically costs $200-400. Treatment options like water softeners, iron filters, and reverse osmosis systems can address multiple 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 ⓘ |
|---|---|---|---|---|---|
| Iron | 101 | 42% | High | High | |
| Sulfate | 104 | 16% | High | High | |
| Manganese | 101 | 11% | High | Moderate | |
| PFHxS ⓘ municipal | 45 | 9% | Moderate | Moderate | |
| PFOS ⓘ municipal | 45 | 9% | Moderate | Moderate | |
| PFOA ⓘ municipal | 45 | 2% | Moderate | Low | |
| Nitrate | 74 | 0% | Moderate | Low | |
| Nitrite | 71 | 0% | Moderate | Low | |
| PFNA ⓘ municipal | 45 | 0% | Moderate | Safe | |
| Radon | 1 | 0% | Low | Low ⓘ | |
| Uranium | 5 | 0% | Low | Low ⓘ | |
| Arsenic | 3 | 0% | Low | Low ⓘ | |
| Chloride | 104 | 0% | High | Low | |
| Fluoride | 97 | 0% | Moderate | Low | |
| HFPO-DA (GenX) ⓘ municipal | 45 | 0% | Moderate | Safe | |
| Lead | 3 | 0% | Low | Low ⓘ | |
| Hardness | 104 | — | High | Low | |
| PFBS ⓘ municipal | 45 | — | Moderate | Low | |
| pH | 77 | — | Moderate | Low | |
| Sodium | 81 | — | 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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