Groundwater in Guadalupe County contains iron, manganese, nitrate, arsenic, chloride, fluoride, sulfate, and PFOS. Several of these contaminants exceed EPA health standards, making them a real concern for well owners in this area.
The rock beneath Guadalupe County naturally contains iron and manganese minerals that dissolve into groundwater over time. Nitrate comes from agricultural fertilizer and septic systems in the area. Arsenic, chloride, fluoride, and sulfate occur naturally in the rock or accumulate where the water moves slowly underground. PFOS is a human-made chemical found in some industrial areas and firefighting foam.
Groundwater in this county is very hard, driven by elevated calcium and magnesium minerals, along with high iron and sodium. The underlying rock releases these minerals as water percolates through, and slow-moving water allows minerals to concentrate. These characteristics are widespread across wells throughout the county.
Wells in Guadalupe County exceed EPA health standards for several contaminants. Arsenic can damage your kidneys and increase cancer risk. Nitrate harms infants and can cause serious illness. Fluoride at high levels weakens bones and teeth. PFOS is a chemical linked to health problems including high cholesterol and immune system effects. Chloride and sulfate at elevated levels can upset your stomach and cause other digestive issues. Manganese can affect your nervous system, especially in children.
The water in this county is very hard, which means scale buildup in your pipes, water heater, and appliances like dishwashers and washing machines. Hard water shortens the lifespan of these appliances. You'll see rust and brown staining on fixtures and laundry. The water may taste salty or have a rotten egg smell from sulfate and other minerals. Soap doesn't lather well and leaves residue on skin and hair.
We recommend a comprehensive water test to find out exactly what is in your well, since every well is different and yours may have higher or lower levels than the county average. Testing is the only way to know what you're drinking and what needs treatment. A comprehensive metals and minerals panel runs between two hundred and four hundred dollars. Depending on your results, treatment options include reverse osmosis systems, water softeners, or activated carbon filters.
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 ⓘ |
|---|---|---|---|---|---|
| Iron | 124 | 43% | High | High | |
| Nitrate | 100 | 33% | High | High | |
| Manganese | 26 | 27% | Moderate | High | |
| Chloride | 148 | 26% | High | High | |
| Sulfate | 123 | 18% | High | High | |
| Arsenic | 25 | 8% | Moderate | Moderate | |
| PFOS ⓘ municipal | 52 | 2% | Moderate | Low | |
| Fluoride | 206 | 1% | High | Low | |
| HFPO-DA (GenX) ⓘ municipal | 52 | 0% | Moderate | Safe | |
| Lead | 25 | 0% | Moderate | Low | |
| Nitrite | 8 | 0% | Low | Low ⓘ | |
| PFHxS ⓘ municipal | 52 | 0% | Moderate | Safe | |
| PFNA ⓘ municipal | 52 | 0% | Moderate | Safe | |
| PFOA ⓘ municipal | 52 | 0% | Moderate | Safe | |
| Radon | 3 | 0% | Low | Low ⓘ | |
| Uranium | 10 | 0% | Low | Low | |
| Hardness | 114 | — | High | Low | |
| PFBS ⓘ municipal | 52 | — | Moderate | Safe | |
| pH | 129 | — | High | Low | |
| Sodium | 114 | — | High | 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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