Groundwater in Collin County contains arsenic, fluoride, iron, manganese, nitrate, and PFOS. Several of these contaminants exceed EPA health standards and warrant attention from well owners.
These contaminants come from two sources. Iron and manganese dissolve naturally from the rocks below as water sits underground. Arsenic and fluoride also occur naturally in the local geology. Nitrate and PFOS enter groundwater from human activities--fertilizer use on land and industrial or consumer products.
Groundwater in this county is marked by elevated iron and manganese from the rocks beneath the surface. As water moves slowly through the ground layers, these metals dissolve into the water. Iron concentrations are moderate across many wells in the county, and manganese is also common in the groundwater here.
Wells in Collin County commonly contain arsenic, fluoride, iron, manganese, nitrate, and PFOS at levels exceeding EPA health standards. Arsenic can harm your kidneys and increase cancer risk with long-term exposure. Fluoride at elevated levels can damage tooth enamel in children. Nitrate is especially concerning for infants and can interfere with oxygen in the blood. Manganese affects brain development in children. PFOS is an industrial chemical linked to health problems including immune and liver effects.
Iron and manganese in county wells create rusty orange or brown stains on sinks, toilets, and laundry that are hard to remove. These minerals can give water a metallic taste and unpleasant odor. The moderate iron levels here can also build up scale inside pipes and water heaters, shortening their lifespan over time.
Every well in this county is different, and your well may have higher or lower levels than what is common here. Testing is the only way to know what is actually in your water so you can treat it properly. We recommend a comprehensive metals and minerals panel since multiple contaminants exceed standards; this typically costs $200 to $400. Treatment options like reverse osmosis systems or whole-house filters can address multiple contaminants at once.
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 | 197 | 20% | High | High | |
| Nitrate | 27 | 7% | Moderate | Moderate | |
| Manganese | 123 | 2% | High | Low | |
| Arsenic | 69 | 1% | Moderate | Low | |
| PFOS ⓘ municipal | 116 | 1% | High | Low | |
| Fluoride | 278 | 1% | High | Low | |
| HFPO-DA (GenX) ⓘ municipal | 116 | 0% | High | Safe | |
| Lead | 63 | 0% | Moderate | Low | |
| PFHxS ⓘ municipal | 116 | 0% | High | Low | |
| PFNA ⓘ municipal | 116 | 0% | High | Safe | |
| PFOA ⓘ municipal | 116 | 0% | High | Safe | |
| Uranium | 7 | 0% | Low | Safe ⓘ | |
| PFBS ⓘ municipal | 116 | — | 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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