Groundwater in Tulare County contains multiple contaminants that exceed EPA health standards, including arsenic, radon, uranium, nitrate, perchlorate, and several others. These levels are serious enough that well owners need to test their water and take action to protect their families.
The contaminants come from two main sources. Nitrate and perchlorate come from agricultural fertilizers and industrial activity across the Central Valley. Arsenic, uranium, and radon occur naturally in the rock and soil layers that hold the groundwater in this region.
Groundwater in Tulare County is hard, driven mainly by calcium and magnesium dissolved from the underground rock layers. The Central Valley's geology creates conditions where these minerals concentrate in the water as it moves slowly through the soil and rock. Hard water is widespread across wells in this county.
Wells in Tulare County commonly contain arsenic, boron, chloride, fluoride, nitrate, nitrite, perchlorate, radon, uranium, and other chemicals at levels that exceed EPA health standards. Arsenic and uranium are known to increase cancer risk with long-term exposure. Nitrate and nitrite can harm infants and affect how blood carries oxygen. Radon is a radioactive gas that raises lung cancer risk. Perchlorate and PFOA and PFOS are industrial chemicals linked to thyroid problems, immune system damage, and other health effects.
The hard water common in county wells leaves scale buildup on faucets and fixtures and can shorten the life of water heaters and dishwashers. You may notice a white crusty coating on shower heads and sink aerators. The moderate sodium content and mineral load can affect the taste of water and your drinking experience over time.
Testing is the only way to know what is actually in your well, since every well is different and yours could have higher or lower levels than what is common in the county. We recommend a comprehensive panel because multiple contaminants exceed health standards in this area--expect to spend $200 to $400 for thorough testing. Treatment options like reverse osmosis, activated carbon filters, or ion exchange systems can address specific contaminants once you know what you are dealing with.
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 ⓘ |
|---|---|---|---|---|---|
| Nitrate | 651 | 25% | High | High | |
| Radon | 31 | 19% | Moderate | High ⓘ | |
| Uranium | 244 | 16% | High | High | |
| Arsenic | 454 | 10% | High | Moderate | |
| PFOS ⓘ municipal | 284 | 6% | High | Moderate | |
| Manganese | 472 | 5% | High | Moderate | |
| Chloride | 675 | 4% | High |
Moderate
Elevated concentration, not % above limit
|
|
| Perchlorate | 124 | 3% | High |
Moderate
Elevated concentration, not % above limit
|
|
| Sulfate | 672 | 3% | High | Low | |
| 1,2,3-Trichloropropane | 277 | 3% | High | Low | |
| Iron | 493 | 2% | High | Low | |
| PFOA ⓘ municipal | 284 | 2% | High | Low | |
| Nitrite | 457 | 1% | High | Low | |
| Boron | 276 | 0% | High | Low | |
| Fluoride | 590 | 0% | High | Low | |
| HFPO-DA (GenX) ⓘ municipal | 282 | 0% | High | Safe | |
| Radium 226 | 13 | 0% | Low | Low | |
| PFNA ⓘ municipal | 284 | 0% | High | Safe | |
| Chromium (total) | 276 | 0% | High | Low | |
| Radium 228 | 13 | 0% | Low | Low | |
| Lead | 356 | 0% | High | Low | |
| PFHxS ⓘ municipal | 284 | 0% | High | Low | |
| Tds | 276 | — | High | Low | |
| Sodium | 674 | — | High | Low | |
| Hardness | 671 | — | High | Low | |
| PFBS ⓘ municipal | 284 | — | High | Low | |
| pH | 631 | — | 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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