Groundwater in Williamson County contains radon, iron, fluoride, chloride, lead, manganese, nitrate, PFOA, PFOS, and sulfate. Several of these contaminants exceed EPA health standards, so well owners should test their water and consider treatment options.
These contaminants come from multiple sources in the county. Radon seeps up from rock layers underground. Iron and manganese occur naturally where groundwater passes through certain rock types. Nitrate and chloride enter from fertilizers, septic systems, and road salt. PFOA and PFOS are industrial chemicals that have contaminated some areas.
Groundwater in Williamson County is very hard, driven by calcium and magnesium dissolved from the local rock. The abundance of these minerals reflects the limestone and other carbonate-rich rock that makes up much of the county's water-bearing layers. Very hard water is the rule across most wells in this county.
Wells in Williamson County have been found to contain several contaminants above EPA health standards. These include chloride, fluoride, iron, lead, manganese, nitrate, PFOA, PFOS, and radon. Lead and radon are especially important because they can harm children's development and increase cancer risk over time. Nitrate affects infants and vulnerable people. Fluoride at high levels can damage teeth and bones. PFOA and PFOS are industrial chemicals that may affect immune system and liver function.
The county's water is very hard, which creates practical challenges in daily life. Hard water leaves spots on dishes and glass, stains on fixtures and clothing, and buildup inside pipes and water heaters. Over time, this hardness can shorten the lifespan of water heaters, dishwashers, and other appliances. You may also notice a chalky or mineral taste in your water.
We recommend testing your well water with a comprehensive panel to find out exactly what is in your water. Every well is different, and your water could have higher or lower levels than what is common in the county. A comprehensive metals and minerals panel costs between $200 and $400. Testing is the only way to know what treatment your household needs, whether that is a water softener, activated carbon filter, or other solutions.
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 ⓘ |
|---|---|---|---|---|---|
| Radon | 3 | 67% | Low | High ⓘ | |
| Iron | 419 | 22% | High | High | |
| Fluoride | 1032 | 14% | High | Moderate | |
| Sulfate | 60 | 5% | Moderate | Moderate | |
| PFOS ⓘ municipal | 123 | 4% | High |
Moderate
Elevated concentration, not % above limit
|
|
| Nitrate | 102 | 3% | High | Low | |
| PFOA ⓘ municipal | 123 | 2% | High | Low | |
| Manganese | 354 | 2% | High | Low | |
| Lead | 137 | 2% | High | Low | |
| Chloride | 60 | 2% | Moderate | Low | |
| Arsenic | 131 | 0% | High | Low | |
| HFPO-DA (GenX) ⓘ municipal | 123 | 0% | High | Safe | |
| Nitrite | 54 | 0% | Moderate | Low | |
| PFHxS ⓘ municipal | 123 | 0% | High | Low | |
| PFNA ⓘ municipal | 123 | 0% | High | Low | |
| Uranium | 57 | 0% | Moderate | Low | |
| E. coli | 3* | 0% | Low | Low ⓘ | |
| Hardness | 61 | — | Moderate | Low | |
| PFBS ⓘ municipal | 123 | — | High | Low | |
| pH | 134 | — | High | Low | |
| Sodium | 61 | — | Moderate | Low | |
| Total Coliform | 3* | 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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