Groundwater in Santa Cruz County contains radon, manganese, iron, arsenic, chloride, nitrate, pfoa, pfos, and sulfate. Multiple contaminants here exceed EPA health standards, making water testing and treatment important for well owners.
These contaminants come from mixed sources. Radon comes from radioactive minerals in the rock itself. Iron and manganese occur naturally where water passes through certain rock types. Arsenic, nitrate, and chloride can seep in from agricultural and urban activities on the land above, or from natural deposits in the rock. Saltwater intrusion near the coast also contributes chloride to some wells.
Groundwater in this county is very hard, driven by elevated calcium and magnesium from the rocks below. Hard water develops where water sits in contact with mineral-rich rock layers for a long time, and this pattern is widespread across Santa Cruz County wells.
Wells in Santa Cruz County commonly contain arsenic, chloride, iron, manganese, nitrate, PFOA, PFOS, radon, and sulfate at levels above EPA health standards. Arsenic can damage your kidneys and increase cancer risk with long-term exposure. Nitrate is especially dangerous for infants and can interfere with oxygen in the blood. Radon is a radioactive gas that increases lung cancer risk. PFOA and PFOS are chemicals linked to health problems including liver damage and immune system effects.
The very hard water in county wells causes real problems at home. You will likely see rust stains on fixtures and laundry, white scale buildup in pipes and on faucets, and reduced water flow over time. Hard water also shortens the lifespan of water heaters and dishwashers. The mineral content can affect how well soap works and leave spots on dishes and glasses.
Testing is the only way to know what is actually in your well. We recommend a comprehensive panel since multiple contaminants exceed health standards in this county, which typically costs $200-400. Every well is different, and yours could have higher or lower levels than what is common here. Water softeners can address hardness, while reverse osmosis or activated carbon filters can help with some 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 | 38 | 47% | Moderate | High ⓘ | |
| Manganese | 346 | 39% | High | High | |
| Iron | 355 | 17% | High | High | |
| Chloride | 2134 | 5% | High | Moderate | |
| PFOS ⓘ municipal | 98 | 4% | Moderate |
Moderate
Elevated concentration, not % above limit
|
|
| Arsenic | 193 | 4% | High |
Moderate
Elevated concentration, not % above limit
|
|
| Nitrate | 94 | 3% | Moderate |
Moderate
Elevated concentration, not % above limit
|
|
| Sulfate | 387 | 3% | High |
Moderate
Elevated concentration, not % above limit
|
|
| PFOA ⓘ municipal | 99 | 2% | Moderate | Low | |
| PFHxS ⓘ municipal | 97 | 0% | Moderate | Low | |
| Lead | 160 | 0% | High | Low | |
| PFNA ⓘ municipal | 98 | 0% | Moderate | Safe | |
| Uranium | 71 | 0% | Moderate | Low | |
| Boron | 29 | 0% | Moderate | Low | |
| Chromium (total) | 29 | 0% | Moderate | Low | |
| 1,2,3-Trichloropropane | 30 | 0% | Moderate | Safe | |
| HFPO-DA (GenX) ⓘ municipal | 98 | 0% | Moderate | Safe | |
| Fluoride | 383 | 0% | High | Low | |
| Nitrite | 92 | 0% | Moderate | Low | |
| Perchlorate | 30 | 0% | Moderate | Low | |
| Tds | 29 | — | Moderate | Low | |
| Sodium | 391 | — | High | Low | |
| Total Coliform | 3* | 0% | Low | Low ⓘ | |
| PFBS ⓘ municipal | 98 | — | Moderate | Low | |
| pH | 2139 | — | High | Low | |
| E. coli | 3* | 0% | Low | Safe ⓘ | |
| Hardness | 391 | — | 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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