Groundwater in Alameda County contains boron, manganese, and nitrate alongside arsenic, chloride, iron, lead, uranium, and PFAS chemicals. Multiple contaminants exceed EPA health standards, making water testing and treatment important for well owners in this area.
These contaminants come from several sources in Alameda County. Naturally occurring arsenic, uranium, and manganese dissolve from the rock layers underground. Nitrate and chloride enter from urban runoff, septic systems, and past agricultural activity. Boron and sulfate also occur naturally in the groundwater here. PFAS chemicals come from industrial use and firefighting activities over decades.
Groundwater in Alameda County is very hard, driven by high levels of calcium and magnesium from the rock layers, along with elevated sodium and sulfate. These minerals dissolve naturally as water moves through the underground rock and soil. Very hard water with high mineral content is common across wells throughout this county.
Wells in Alameda County commonly exceed EPA health standards for arsenic, boron, chloride, lead, nitrate, uranium, and PFOA/PFOS compounds. Arsenic and uranium are radioactive metals that can damage your kidneys and bones with long-term exposure. Lead harms children's brain development and causes learning problems. Nitrate is especially dangerous for babies and can prevent their blood from carrying oxygen. PFOA and PFOS are industrial chemicals that build up in your body and raise risks for liver damage and cancer.
The very hard water in county wells causes real problems at home. Scale builds up inside pipes and water heaters, shortening their lifespan by years. You will see rust stains on sinks and laundry that are hard to remove. The water tastes salty and mineral-heavy. Appliances like dishwashers and water heaters wear out faster because of the mineral buildup.
We recommend testing your well with a comprehensive panel because multiple health contaminants are common here. Every well is different, and yours could have higher or lower levels than the county average. Testing is the only way to know what is actually in your water so you can treat it properly. A comprehensive metals and minerals panel runs about two to four hundred dollars. Ion exchange or activated carbon filters can address many of these 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 ⓘ |
|---|---|---|---|---|---|
| Boron | 1 | 100% | Low | High ⓘ | |
| Manganese | 841 | 40% | High | High | |
| Nitrate | 3967 | 17% | High | High | |
| PFOS ⓘ municipal | 87 | 16% | Moderate | High | |
| Chloride | 4304 | 13% | High | Moderate | |
| Sulfate | 1318 | 8% | High | Moderate | |
| Iron | 1101 | 8% | High | Moderate | |
| PFOA ⓘ municipal | 87 | 6% | Moderate | Moderate | |
| Arsenic | 127 | 6% | High | Moderate | |
| Uranium | 67 | 3% | Moderate | Low | |
| Lead | 104 | 3% | High | Low | |
| PFHxS ⓘ municipal | 87 | 2% | Moderate | Low | |
| Radon | 14 | 0% | Low | Low ⓘ | |
| PFNA ⓘ municipal | 87 | 0% | Moderate | Safe | |
| Chromium (total) | 1 | 0% | Low | Low ⓘ | |
| 1,2,3-Trichloropropane | 1 | 0% | Low | Safe ⓘ | |
| Fluoride | 1810 | 0% | High | Low | |
| HFPO-DA (GenX) ⓘ municipal | 87 | 0% | Moderate | Safe | |
| Nitrite | 2972 | 0% | High | Low | |
| Perchlorate | 1 | 0% | Low | Low ⓘ | |
| Tds | 1 | — | Low | Low ⓘ | |
| pH | 1 | — | Low | Low ⓘ | |
| Hardness | 2275 | — | High | Low | |
| PFBS ⓘ municipal | 87 | — | Moderate | Low | |
| Sodium | 1258 | — | 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.
Loading recent water news…