Groundwater in Smyth County contains chloride, radon, and arsenic at levels high enough to exceed EPA health standards. These contaminants are present in amounts that well owners should know about and may want to address.
The Valley and Ridge geology here creates conditions where these contaminants enter groundwater. Arsenic occurs naturally in the bedrock and soil; radon is released from radioactive minerals in the rock; and chloride comes from both natural mineral deposits in the earth and from road salt and other sources on the land surface. Water moving through cracks and layers in the rock picks up all three.
Groundwater in this county is soft, with low iron, sodium, and sulfate levels that keep the water clean-tasting and uncomplicated. The rock layers here do not contain the limestone or minerals that would add hardness or iron to the water. These low mineral levels are found across most wells in the county.
Wells in Smyth County can contain arsenic, chloride, and radon at levels that exceed EPA health standards. Arsenic is a poison that builds up in your body over time and can cause cancer, heart disease, and other serious illnesses. Radon is a radioactive gas that comes from rocks underground and increases your risk of lung cancer when you breathe it in. Chloride at high levels can harm people with certain health conditions like heart or kidney problems.
The good news is that wells in this county generally have low levels of minerals like iron and sodium, so you probably won't see orange staining, salty taste, or buildup in your pipes and appliances. Your water should feel and taste fairly normal compared to wells in other areas with mineral problems.
We recommend testing your well water to find out what is actually in it, since every well is different and yours could have higher or lower levels than what is common in the county. A comprehensive test for metals and minerals typically costs $200 to $400 and is the only way to know if treatment is needed. Treatment options like activated carbon filters or aeration can address some of these contaminants, depending on what testing shows.
| Contaminant | Samples ⓘ | % Above MCL ⓘ | Distribution ⓘ | Confidence ⓘ | Risk ⓘ |
|---|---|---|---|---|---|
| Hardness | 7 | — | Low | Low ⓘ | |
| PFBS ⓘ municipal | 16 | — | Moderate | Safe | |
| pH | 4 | — | Low | Low ⓘ | |
| Sodium | 7 | — | 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.
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