Groundwater in Grimes County contains radon, manganese, iron, arsenic, chloride, nitrate, and sulfate at levels that exceed EPA health standards. These contaminants are present at concentrations the EPA considers concerning enough to warrant attention.
The rock and soil in this area naturally contain iron and manganese, which dissolve into groundwater as it moves through the ground. Radon comes from radioactive minerals in the rock. Nitrate and chloride often come from fertilizers, septic systems, and road salt used on land above. Arsenic occurs naturally in some rock layers in this region and can be released into water over time.
Groundwater in Grimes County is very hard, driven by high levels of calcium and magnesium from the rock formations below, along with elevated sodium. These minerals accumulate because water spends time moving through rock that contains them, dissolving them slowly. Very hard water with high sodium is a common finding across wells throughout this county.
Wells in Grimes County commonly have arsenic, nitrate, radon, and manganese at levels that exceed EPA health standards. Arsenic and radon increase the risk of cancer over time. Nitrate can harm infants and cause other health problems. Manganese can affect brain development in children and cause nervous system issues in adults.
The county's water is very hard, which leaves white scale buildup on faucets, shower heads, and inside pipes. Hard water makes soap less effective and can shorten the lifespan of water heaters and dishwashers. High sodium in wells here can leave a salty taste and is a concern for people on low-sodium diets.
We recommend testing your well with a comprehensive panel since multiple contaminants are found in county wells. Every well is different, so your water may have higher or lower levels than what is common here. Testing is the only way to know what is actually in your well so you can treat it properly. A comprehensive panel usually costs between two hundred and four hundred dollars. Water softeners can address hardness, and carbon or reverse osmosis filters can help with specific contaminants.
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 | 1 | 100% | Low | High ⓘ | |
| Manganese | 57 | 37% | Moderate | High | |
| Iron | 231 | 29% | High | High | |
| Sulfate | 150 | 20% | High | High | |
| Chloride | 150 | 18% | High | High | |
| Nitrate | 158 | 11% | High | Moderate | |
| Arsenic | 53 | 8% | Moderate | Moderate | |
| Fluoride | 372 | 0% | High | Low | |
| HFPO-DA (GenX) ⓘ municipal | 6 | 0% | Low | Safe ⓘ | |
| Lead | 53 | 0% | Moderate | Low | |
| Nitrite | 1 | 0% | Low | Safe ⓘ | |
| PFHxS ⓘ municipal | 6 | 0% | Low | Safe ⓘ | |
| PFNA ⓘ municipal | 6 | 0% | Low | Safe ⓘ | |
| PFOA ⓘ municipal | 6 | 0% | Low | Safe ⓘ | |
| PFOS ⓘ municipal | 6 | 0% | Low | Safe ⓘ | |
| Uranium | 11 | 0% | Low | Safe | |
| Hardness | 148 | — | High | Low | |
| PFBS ⓘ municipal | 6 | — | Low | Safe ⓘ | |
| pH | 138 | — | High | Low | |
| Sodium | 145 | — | 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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