Groundwater in Gonzales County contains arsenic, chloride, fluoride, iron, lead, manganese, nitrate, and sulfate at levels exceeding EPA health standards. These contaminants are present at concentrations serious enough to warrant testing and attention from well owners.
The rock layers beneath this county naturally release many of these metals and salts into the groundwater. Iron and manganese come from the surrounding rock, while chloride, sulfate, and fluoride dissolve from the same geological formations. Nitrate enters from agricultural activity and septic systems in the area, accumulating in the aquifer where it persists.
Groundwater in this county is moderately hard and elevated in sodium, driven by iron and the high sodium concentration naturally present in the rock. The Texas coastal uplands aquifer system here contains rock rich in these minerals, which dissolve slowly into water as it moves underground. These characteristics are widespread across wells throughout the county, reflecting the consistent geology beneath the region.
Wells in Gonzales County commonly contain arsenic, lead, nitrate, fluoride, chloride, and manganese at levels above EPA health standards. Arsenic can harm your kidneys and increase cancer risk. Lead damages children's brain development and learning. Nitrate is especially dangerous for babies and can cause serious illness. Fluoride at elevated levels can weaken bones. Manganese affects your nervous system and can cause problems with movement and memory.
The county's water also contains moderate iron and high sodium, which create quality-of-life problems. Iron leaves orange or brown stains on fixtures, laundry, and dishes that are hard to remove. High sodium gives the water a salty taste. The moderately hard water can build up scale inside pipes and water heaters, shortening the lifespan of appliances like dishwashers and hot water tanks.
Since every well is different and your water may have higher or lower levels than what is common in the county, we recommend testing. A comprehensive metals and minerals panel will show you exactly what is in your well so it can be treated properly. Testing costs between two hundred and four hundred dollars. Treatment options like reverse osmosis systems or activated carbon filters can address multiple contaminants depending on your results.
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 | 288 | 35% | High | High | |
| Iron | 386 | 29% | High | High | |
| Chloride | 191 | 28% | High | High | |
| Sulfate | 188 | 15% | High | High | |
| Nitrate | 219 | 10% | High | Moderate | |
| Fluoride | 669 | 5% | High | Moderate | |
| Lead | 226 | 1% | High | Low | |
| Arsenic | 231 | 0% | High | Low | |
| HFPO-DA (GenX) ⓘ municipal | 24 | 0% | Moderate | Safe | |
| Nitrite | 8 | 0% | Low | Low ⓘ | |
| PFHxS ⓘ municipal | 24 | 0% | Moderate | Safe | |
| PFNA ⓘ municipal | 24 | 0% | Moderate | Safe | |
| PFOA ⓘ municipal | 24 | 0% | Moderate | Safe | |
| PFOS ⓘ municipal | 24 | 0% | Moderate | Safe | |
| Radon | 2 | 0% | Low | Low ⓘ | |
| Uranium | 27 | 0% | Moderate | Safe | |
| PFBS ⓘ municipal | 24 | — | Moderate | Low | |
| pH | 186 | — | High | Low | |
| Sodium | 187 | — | High | Low | |
| Hardness | 187 | — | 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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