Groundwater in Washington County contains manganese, nitrate, iron, arsenic, chloride, and sulfate. Several of these contaminants exceed EPA health standards and deserve attention.
The rock beneath Washington County naturally contains iron and manganese, which dissolve into groundwater as water moves through the ground. Nitrate enters from fertilizer and septic systems in farming and residential areas. Arsenic and chloride also come from the rock layers themselves. Sulfate appears at low levels from natural sources in the soil.
Groundwater in this county is very hard, driven by elevated calcium and magnesium from the limestone and mineral-rich rock below. The water also contains moderate amounts of iron and sodium. These characteristics are widespread across wells throughout the county.
Wells in Washington County contain arsenic, chloride, iron, manganese, nitrate, and sulfate at levels that exceed EPA health standards. Arsenic exposure over time can increase the risk of cancer and harm the kidneys and nervous system. Nitrate is especially concerning for infants and can interfere with how blood carries oxygen. Manganese at elevated levels can affect brain development and the nervous system, while chloride itself is not a direct health threat but signals saltwater intrusion or other contamination pathways.
County well water is very hard, which means soap works less effectively and clothes can feel sticky after washing. Orange or brown staining on fixtures and in laundry comes from iron in the water. Manganese leaves dark brown or black stains. The buildup of minerals can form scale inside pipes and water heaters, and this very hard water can shorten the life of appliances like dishwashers and water heaters. Some people notice a metallic or salty taste.
Every well is different, and your water could have much higher or lower levels than what is common here. Testing is the only way to know what is actually in your well so it can be treated properly. We recommend a comprehensive metals and minerals panel, which typically costs between $200 and $400. Water softeners can address hardness, and iron filters or reverse osmosis systems can help with other 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 | 81 | 35% | Moderate | High | |
| Nitrate | 130 | 31% | High | High | |
| Iron | 121 | 26% | High | High | |
| Arsenic | 50 | 10% | Moderate | Moderate | |
| Chloride | 170 | 8% | High | Moderate | |
| Sulfate | 169 | 2% | High | Low | |
| Fluoride | 314 | 0% | High | Low | |
| HFPO-DA (GenX) ⓘ municipal | 6 | 0% | Low | Safe ⓘ | |
| Lead | 50 | 0% | Moderate | Low | |
| PFHxS ⓘ municipal | 6 | 0% | Low | Safe ⓘ | |
| PFNA ⓘ municipal | 6 | 0% | Low | Safe ⓘ | |
| PFOA ⓘ municipal | 6 | 0% | Low | Safe ⓘ | |
| PFOS ⓘ municipal | 6 | 0% | Low | Safe ⓘ | |
| Uranium | 9 | 0% | Low | Low ⓘ | |
| Sodium | 137 | — | High | Low | |
| pH | 66 | — | Moderate | Low | |
| PFBS ⓘ municipal | 6 | — | Low | Safe ⓘ | |
| Hardness | 137 | — | 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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