Groundwater in Orange County contains arsenic, fluoride, iron, manganese, nitrate, nitrite, uranium, radon, and PFOS and related chemicals. Multiple contaminants exceed EPA health standards in wells throughout the county, making testing and treatment important for your water supply.
Orange County's geology and land use combine to create these contamination patterns. The varied rock types beneath the county include materials that naturally release arsenic, uranium, and radon. Nitrate and nitrite come from fertilizer use and urban development. PFOS and related chemicals come from industrial sites, airports, and firefighting foam used at military bases and civilian airports in the region.
Groundwater in Orange County is very hard, driven by high sodium and elevated hardness minerals that accumulate as water moves through the underlying rocks. This hardness is widespread across the county's wells. Iron is present at low levels, so it is not the main character of the water.
Wells in Orange County have been found to contain arsenic, fluoride, uranium, radon, nitrate, nitrite, and a group of chemicals called PFAS compounds--all at levels that exceed EPA health standards. Arsenic and uranium are radioactive elements that can damage kidneys and bones with long-term exposure. Radon is a radioactive gas that increases lung cancer risk. Nitrate and nitrite harm infants and can affect how blood carries oxygen. PFAS chemicals build up in your body and can affect your immune system and liver.
County wells show very hard water, which causes white scale buildup on faucets, fixtures, and inside pipes. Hard water makes soap work poorly and leaves spots on dishes and glassware. The high sodium in many county wells adds a salty taste that some people notice right away. Very hard water also shortens the lifespan of water heaters, dishwashers, and other appliances by years.
We recommend testing your well right away through a comprehensive metals and minerals panel, which costs roughly two hundred to four hundred dollars. Your well is different from others in the county--it could have higher or lower levels of these contaminants. Testing is the only way to know exactly what is in your water so you can treat it properly. Water softeners address hardness, while activated carbon and reverse osmosis can help with some chemical 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 ⓘ |
|---|---|---|---|---|---|
| Manganese | 174 | 26% | High | High | |
| Radon | 63 | 14% | Moderate | Moderate ⓘ | |
| PFOS ⓘ municipal | 436 | 10% | High | Moderate | |
| Uranium | 122 | 10% | High | Moderate | |
| Iron | 175 | 9% | High | Moderate | |
| PFOA ⓘ municipal | 436 | 7% | High | Moderate | |
| Arsenic | 131 | 4% | High |
Moderate
Elevated concentration, not % above limit
|
|
| Nitrate | 1664 | 3% | High | Low | |
| PFHxS ⓘ municipal | 436 | 1% | High | Low | |
| Nitrite | 151 | 1% | High | Low | |
| Fluoride | 1490 | 0% | High | Low | |
| Chromium (total) | 1 | 0% | Low | Safe ⓘ | |
| 1,2,3-Trichloropropane | 1 | 0% | Low | Safe ⓘ | |
| HFPO-DA (GenX) ⓘ municipal | 436 | 0% | High | Safe | |
| Lead | 116 | 0% | High | Low | |
| Perchlorate | 1 | 0% | Low | Safe ⓘ | |
| PFNA ⓘ municipal | 436 | 0% | High | Safe | |
| pH | 1 | — | Low | Low ⓘ | |
| PFBS ⓘ municipal | 436 | — | High | Low | |
| Hardness | 1870 | — | High | Low | |
| Sodium | 1799 | — | 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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