Groundwater in Riverside County contains arsenic, boron, chloride, fluoride, lead, manganese, nitrate, radon, uranium, and pfas chemicals like PFOA and PFOS. These contaminants exceed EPA health standards in this county, making them a real concern for well owners.
The region's geology and human activities both drive these contamination patterns. The varied rock types here naturally contain arsenic and uranium. Agricultural use introduces nitrate and chloride into groundwater. Industrial activity, past and present, has deposited pfas chemicals. Radon seeps in from radioactive elements in the surrounding rock. These sources combine to create a complex contamination picture across the county.
Groundwater in Riverside County is hard and elevated in sodium and sulfate, with moderate sulfate levels from the dissolving minerals in the rock and soil. The rock types and mineral-rich layers here naturally concentrate these dissolved solids as water moves through them. These characteristics are widespread across wells throughout the county.
Wells in Riverside County show high levels of arsenic, uranium, nitrate, lead, radon, and PFOA and PFOS chemicals. Arsenic and uranium are radioactive elements that build up in your body over time and increase cancer risk. Lead harms children's brain development and causes learning problems. Nitrate is dangerous for infants and can interfere with oxygen in the blood. Radon, a radioactive gas, increases lung cancer risk when you breathe it in. PFOA and PFOS are industrial chemicals linked to liver damage, thyroid disease, and cancer.
County wells also contain high amounts of salt, sulfate, and hardness minerals that affect daily life. The hard water leaves white scale buildup on faucets, shower heads, and dishes. It makes soap less effective and leaves your skin and hair feeling sticky. Hard water shortens the lifespan of water heaters, dishwashers, and washing machines. You may notice a salty or bitter taste in the water.
We recommend a comprehensive water test right away since Riverside County wells have many different contaminants. Every well is different, and your well could have much 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. A full panel costs between $200 and $400 and can identify treatment needs like reverse osmosis filters or activated carbon systems.
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 ⓘ |
|---|---|---|---|---|---|
| Sulfate | 4091 | 23% | High | High | |
| Manganese | 1944 | 10% | High | Moderate | |
| Radon | 96 | 10% | Moderate | Moderate ⓘ | |
| Nitrate | 3603 | 7% | High | Moderate | |
| Chloride | 4237 | 7% | High | Moderate | |
| Arsenic | 1277 | 5% | High | Moderate | |
| Boron | 41 | 5% | Moderate |
Moderate
Elevated concentration, not % above limit
|
|
| Fluoride | 3576 | 5% | High |
Moderate
Elevated concentration, not % above limit
|
|
| PFOA ⓘ municipal | 538 | 3% | High |
Moderate
Elevated concentration, not % above limit
|
|
| Iron | 2262 | 3% | High |
Moderate
Elevated concentration, not % above limit
|
|
| Uranium | 612 | 3% | High | Low | |
| Lead | 734 | 3% | High | Low | |
| PFOS ⓘ municipal | 538 | 3% | High | Low | |
| PFHxS ⓘ municipal | 536 | 0% | High | Low | |
| Chromium (total) | 41 | 0% | Moderate | Low | |
| 1,2,3-Trichloropropane | 41 | 0% | Moderate | Safe | |
| PFNA ⓘ municipal | 538 | 0% | High | Low | |
| HFPO-DA (GenX) ⓘ municipal | 536 | 0% | High | Safe | |
| Nitrite | 1499 | 0% | High | Low | |
| Perchlorate | 41 | 0% | Moderate | Low | |
| Tds | 41 | — | Moderate | Low | |
| Hardness | 4414 | — | High | Low | |
| Sodium | 4152 | — | High | Low | |
| pH | 4301 | — | High | Low | |
| PFBS ⓘ municipal | 536 | — | High | Low | |
| Total Coliform | 44* | 0% | Moderate | Low | |
| E. coli | 44* | 0% | Moderate | 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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