Cobb County groundwater contains arsenic, fluoride, iron, lead, manganese, radon, and sulfate at levels that exceed EPA health standards. Several of these contaminants are present at concerning concentrations and require attention from well owners.
These contaminants come from the crystalline rock that underlies the county. As water moves through granite and metamorphic rock, it dissolves naturally occurring metals like iron, manganese, and arsenic. Sulfate also leaches from minerals in the bedrock. Radon forms from radioactive decay within the rock itself.
Cobb County groundwater is moderately hard and notably high in sulfate, with elevated iron and manganese from the crystalline rock below. These minerals dissolve as water passes through the granite and metamorphic bedrock that supplies private wells throughout the county. Most wells in Cobb County show these mineral characteristics to some degree.
Wells in Cobb County commonly contain arsenic, fluoride, lead, manganese, and radon at levels that exceed EPA health standards. Arsenic damages the kidneys and increases cancer risk. Lead harms brain development in children and raises blood pressure in adults. Radon is a radioactive gas that causes lung cancer when breathed over time. Manganese and fluoride affect the nervous system and bone health at elevated levels.
County wells show moderately hard water with elevated sulfate. You may see orange or brown staining on fixtures and laundry from iron and manganese. Sulfate can create a bitter or salty taste. Hard water leaves scale buildup on appliances, and over time this reduces how well water heaters and dishwashers work and can shorten their lifespan.
Testing is the only way to know 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. We recommend a comprehensive panel that checks for metals, minerals, bacteria, and radon since multiple contaminants exceed health standards here--this usually costs $200-400. Treatment options like activated carbon filters, reverse osmosis systems, and aeration can address different contaminants once you know what you're dealing with.
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 | 69 | 64% | Moderate | High | |
| Iron | 110 | 41% | High | High | |
| Sulfate | 122 | 34% | High | High | |
| Radon | 12 | 8% | Low | Moderate ⓘ | |
| Lead | 83 | 5% | Moderate |
Moderate
Elevated concentration, not % above limit
|
|
| Arsenic | 83 | 1% | Moderate | Low | |
| Fluoride | 114 | 1% | High | Low | |
| PFNA ⓘ municipal | 16 | 0% | Moderate | Safe | |
| PFOA ⓘ municipal | 16 | 0% | Moderate | Safe | |
| Chloride | 128 | 0% | High | Low | |
| Nitrite | 97 | 0% | Moderate | Low | |
| Uranium | 12 | 0% | Low | Safe | |
| PFOS ⓘ municipal | 16 | 0% | Moderate | Safe | |
| PFOA ⓘ municipal | 16 | 0% | Moderate | Safe | |
| PFNA ⓘ municipal | 16 | 0% | Moderate | Safe | |
| PFHxS ⓘ municipal | 16 | 0% | Moderate | Safe | |
| Nitrite | 97 | 0% | Moderate | Low | |
| Nitrate | 106 | 0% | High | Low | |
| HFPO-DA (GenX) ⓘ municipal | 16 | 0% | Moderate | Safe | |
| Chloride | 128 | 0% | High | Low | |
| Sodium | 126 | — | High | Low | |
| pH | 136 | — | High | Low | |
| PFBS ⓘ municipal | 16 | — | Moderate | Low | |
| Hardness | 46 | — | 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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