Groundwater in Nassau County contains iron, manganese, arsenic, lead, nitrate, chloride, fluoride, and pfoa among other contaminants. Several of these contaminants exceed EPA health standards and warrant attention from well owners.
These contaminants come from two sources. Iron and manganese dissolve naturally from the sandy and gravelly layers that make up the aquifer beneath Nassau County. Arsenic, lead, nitrate, chloride, and the pfoa chemicals enter from human activities--old pipes, road salt, septic systems, industrial sites, and past disposal practices that have seeped down into the groundwater over decades.
Groundwater in Nassau County is soft with moderate iron content. The sandy aquifer naturally releases iron as water moves through it, and this iron concentration appears across many wells in the county. These characteristics are common enough that well owners should be aware of them when planning for water testing and potential treatment.
Wells in Nassau County commonly exceed EPA health standards for arsenic, chloride, fluoride, lead, manganese, nitrate, nitrite, and PFAS chemicals like PFOA and PFOS. Arsenic and lead can harm the brain and nervous system, especially in children. Manganese affects brain development. Nitrate and nitrite interfere with how blood carries oxygen. PFAS chemicals are linked to liver problems and immune system effects.
Wells in this county have soft water with moderate iron levels. You might notice rust-colored staining on clothes, sinks, and fixtures, or a metallic taste in the water. Iron buildup inside pipes can reduce water flow over time. The good news is that the water is not extremely hard, so appliance damage from mineral scale is not a major concern here.
We recommend a comprehensive metals and minerals panel to find out what is actually in your well, since every well is different and your water may have higher or lower levels than what is common in the county. Testing is the only way to know what needs treatment. A comprehensive panel typically costs $200 to $400. Depending on your results, treatment options include reverse osmosis filters or activated carbon systems for PFAS removal.
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 | 15506 | 33% | High | High | |
| Manganese | 15230 | 19% | High | High | |
| PFOA ⓘ municipal | 374 | 7% | High | Moderate | |
| Nitrate | 15474 | 5% | High | Moderate | |
| PFOS ⓘ municipal | 374 | 2% | High | Low | |
| Chloride | 17777 | 2% | High | Low | |
| Lead | 3469 | 2% | High | Low | |
| PFNA ⓘ municipal | 374 | 1% | High | Low | |
| Sulfate | 11115 | 1% | High | Low | |
| Arsenic | 2308 | 0% | High | Low | |
| Nitrite | 15138 | 0% | High | Low | |
| Fluoride | 6825 | 0% | High | Low | |
| HFPO-DA (GenX) ⓘ municipal | 374 | 0% | High | Safe | |
| PFHxS ⓘ municipal | 374 | 0% | High | Low | |
| Radon | 9 | 0% | Low | Low ⓘ | |
| Uranium | 22 | 0% | Moderate | Low | |
| PFBS ⓘ municipal | 374 | — | High | Low | |
| Hardness | 15318 | — | High | Low | |
| Fecal Coliform | 3* | 0% | Low | Low ⓘ | |
| E. coli | 4* | 0% | Low | Safe ⓘ | |
| pH | 16882 | — | High | Low | |
| Sodium | 10355 | — | High | Low | |
| Total Coliform | 4* | 0% | Low | 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.
Loading recent water news…