Groundwater in Onondaga County contains arsenic, chloride, iron, manganese, nitrate, radon, and sulfate at levels that exceed EPA health standards. Several of these contaminants reach concerning concentrations that warrant attention from well owners.
The sandstone beneath this county naturally releases iron and manganese as water moves through it over time. Chloride and nitrate enter from road salt, fertilizer, and septic systems at the surface, then seep down into the water supply. Radon comes from natural radioactive decay in the bedrock and dissolves into groundwater as it travels underground.
Groundwater in this county is very hard, driven by elevated calcium and magnesium that dissolve from the rock as water passes through it. Sodium levels are also high, which adds to the mineral load in the water. These characteristics are widespread across wells throughout the county.
Wells in Onondaga County commonly contain arsenic, nitrate, radon, and elevated levels of iron and manganese above EPA health standards. Arsenic can damage organs and increase cancer risk with long-term exposure. Nitrate is especially harmful to infants and can interfere with oxygen in the blood. Radon is a radioactive gas that increases lung cancer risk. Iron and manganese above health limits can cause problems in the brain and nervous system, particularly in children.
The water in this county is very hard, which creates practical problems in your home. You will likely see white scale buildup on faucets and inside pipes, and your water heater and dishwasher may wear out faster than normal. The elevated iron can cause rust-colored staining on sinks, toilets, and laundry. Some people notice a metallic taste or smell in their water.
A comprehensive metals and minerals panel is recommended for your well since multiple contaminants exceed health standards--testing typically costs $200 to $400. 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 exactly what is in your water so you can treat it properly. Water softeners, radon ventilation systems, and iron filters are treatment options depending on your results.
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 ⓘ |
|---|---|---|---|---|---|
| Chloride | 270 | 47% | High | High | |
| Sulfate | 258 | 33% | High | High | |
| Manganese | 218 | 32% | High | High | |
| Iron | 255 | 24% | High | High | |
| Radon | 17 | 24% | Moderate | High ⓘ | |
| Arsenic | 29 | 3% | Moderate |
Moderate
Elevated concentration, not % above limit
|
|
| Nitrate | 97 | 1% | Moderate | Low | |
| Fluoride | 88 | 0% | Moderate | Low | |
| HFPO-DA (GenX) ⓘ municipal | 40 | 0% | Moderate | Safe | |
| Lead | 29 | 0% | Moderate | Low | |
| Nitrite | 56 | 0% | Moderate | Low | |
| PFHxS ⓘ municipal | 40 | 0% | Moderate | Safe | |
| PFNA ⓘ municipal | 40 | 0% | Moderate | Safe | |
| PFOA ⓘ municipal | 40 | 0% | Moderate | Safe | |
| PFOS ⓘ municipal | 40 | 0% | Moderate | Safe | |
| Uranium | 17 | 0% | Moderate | Low | |
| E. coli | 7* | 0% | Low | Safe ⓘ | |
| Fecal Coliform | 7* | 0% | Low | Low ⓘ | |
| Hardness | 249 | — | High | Low | |
| PFBS ⓘ municipal | 40 | — | Moderate | Low | |
| pH | 271 | — | High | Low | |
| Sodium | 243 | — | High | Low | |
| Total Coliform | 7* | 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.
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