Groundwater in Ventura County contains sulfate, manganese, chloride, arsenic, fluoride, iron, nitrate, and PFOA and PFOS at levels that exceed EPA health standards. These contaminants reach concerning concentrations, with sulfate at very high levels and the water itself registering as very hard.
The rock layers beneath Ventura County naturally contain minerals and salts that dissolve into groundwater over time. Sulfate and chloride come from the local rock itself, while arsenic, fluoride, and iron occur naturally in these formations. Nitrate enters from agricultural and urban land use above. PFOA and PFOS are human-made chemicals that have contaminated some wells through industrial or firefighting activities.
Groundwater in Ventura County is very hard, with very high sulfate and sodium as the dominant minerals driving that character. These salts concentrate because water moving through the local rock dissolves them steadily as it flows underground. Most wells in this county show these same characteristics.
Wells in Ventura County exceed EPA health standards for several contaminants including arsenic, radon, nitrate, fluoride, chloride, and PFOA and PFOS chemicals. Arsenic and radon can increase cancer risk with long-term exposure. Nitrate harms infants and affects how blood carries oxygen. PFOA and PFOS build up in your body and can affect your immune system and liver. Fluoride at high levels can damage teeth and bones.
The water in this county is very hard and mineral-rich, which creates visible problems in your home. You will see orange or brown staining from iron in sinks, toilets, and laundry. Scale buildup damages water heaters and dishwashers, shortening their lifespan. The water tastes salty from high sodium and can smell like rotten eggs from sulfate. Pipes and fixtures corrode faster in this type of water.
We recommend testing your well with a comprehensive panel because multiple contaminants exceed health standards and every well is different. Your well may have higher or lower levels than what is common in the county--testing is the only way to know what you are actually drinking. A comprehensive metals and minerals panel costs between $200 and $400 and will show exactly what needs treatment. Treatment options like reverse osmosis, activated carbon filters, or water softeners can address different contaminants based on your specific 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 ⓘ |
|---|---|---|---|---|---|
| Sulfate | 601 | 74% | High | High | |
| Manganese | 507 | 56% | High | High | |
| Chloride | 926 | 27% | High | High | |
| Iron | 520 | 20% | High | High | |
| Radon | 10 | 10% | Low | Moderate ⓘ | |
| Nitrate | 476 | 7% | High | Moderate | |
| PFOA ⓘ municipal | 140 | 5% | High | Moderate | |
| PFOS ⓘ municipal | 140 | 3% | High | Low | |
| Arsenic | 106 | 1% | High | Low | |
| Fluoride | 574 | 0% | High | Low | |
| HFPO-DA (GenX) ⓘ municipal | 140 | 0% | High | Safe | |
| Nitrite | 393 | 0% | High | Low | |
| Perchlorate | 1 | 0% | Low | Low ⓘ | |
| Uranium | 66 | 0% | Moderate | Low | |
| Boron | 1 | 0% | Low | Low ⓘ | |
| PFNA ⓘ municipal | 140 | 0% | High | Safe | |
| Chromium (total) | 1 | 0% | Low | Low ⓘ | |
| 1,2,3-Trichloropropane | 1 | 0% | Low | Safe ⓘ | |
| Lead | 60 | 0% | Moderate | Low | |
| PFHxS ⓘ municipal | 140 | 0% | High | Low | |
| Tds | 1 | — | Low | Low ⓘ | |
| Sodium | 588 | — | High | Low | |
| Hardness | 593 | — | High | Low | |
| PFBS ⓘ municipal | 140 | — | High | Low | |
| pH | 635 | — | 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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