Groundwater in Hays County contains sulfate, chloride, and iron along with arsenic, fluoride, lead, manganese, and nitrate at levels that exceed EPA health standards. These contamination levels are concerning enough that well owners should be aware of them.
The rock beneath this county naturally releases arsenic, iron, and manganese into groundwater as water moves through it over time. Nitrate enters from fertilizer and septic systems in areas with agriculture or scattered development. Chloride and sulfate also occur naturally in the rock layers here, though human activities like road salt application can add more.
Groundwater in this county is very hard, driven by elevated calcium and magnesium that dissolve from the rock as water flows through it. The very hard water reflects the mineral-rich character of the underlying geology in this region. These characteristics are widespread across wells throughout Hays County.
Wells in Hays County exceed EPA health standards for arsenic, lead, nitrate, fluoride, chloride, and manganese. Arsenic and lead can harm your kidneys and nervous system with long-term exposure. Nitrate is especially dangerous for babies and can prevent oxygen from reaching their blood. Manganese can affect how your nervous system works. Fluoride at elevated levels can damage bones and teeth during development.
The water in this county is very hard, which means scale builds up inside pipes and water heaters. You'll probably see rust and orange staining on fixtures and laundry from iron. Hard water shortens the lifespan of water heaters and dishwashers. The water may taste chalky or have an unpleasant odor from sulfate, and soap doesn't lather well.
We recommend testing your well because every well is different--yours could have higher or lower levels than what's common in the county. A comprehensive metals and minerals panel costs $200-400 and is the only way to know what's actually in your water so it can be properly treated. Water softeners and iron filters are common treatment options.
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 ⓘ |
|---|---|---|---|---|---|
| Sulfate | 730 | 22% | High | High | |
| Chloride | 729 | 13% | High | Moderate | |
| Iron | 925 | 12% | High | Moderate | |
| Fluoride | 1554 | 6% | High | Moderate | |
| Manganese | 817 | 2% | High | Low | |
| Arsenic | 780 | 1% | High | Low | |
| Nitrate | 607 | 0% | High | Low | |
| Lead | 700 | 0% | High | Low | |
| HFPO-DA (GenX) ⓘ municipal | 101 | 0% | High | Safe | |
| Nitrite | 447 | 0% | High | Low | |
| PFHxS ⓘ municipal | 101 | 0% | High | Low | |
| PFNA ⓘ municipal | 101 | 0% | High | Safe | |
| PFOA ⓘ municipal | 101 | 0% | High | Safe | |
| PFOS ⓘ municipal | 101 | 0% | High | Safe | |
| Radon | 9 | 0% | Low | Low ⓘ | |
| Uranium | 383 | 0% | High | Low | |
| E. coli | 5* | 0% | Low | Low ⓘ | |
| Hardness | 700 | — | High | Low | |
| PFBS ⓘ municipal | 101 | — | High | Low | |
| pH | 768 | — | High | Low | |
| Sodium | 470 | — | High | Low | |
| Total Coliform | 5* | 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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