Orange County groundwater contains radon, manganese, iron, arsenic, chloride, fluoride, lead, nitrate, and uranium. Several of these contaminants exceed EPA health standards and deserve attention, though the levels vary by location.
These contaminants come from different sources in the rock below. Radon seeps naturally from the rock itself. Manganese and iron dissolve from minerals in the bedrock and become concentrated in groundwater over time. Arsenic, uranium, and lead also occur naturally in the local rock. Nitrate and chloride often come from human activity like septic systems and road salt.
Groundwater in this county is hard, driven by calcium and magnesium from the bedrock. The rock type here creates conditions where these minerals dissolve into the water as it flows underground. Hardness is a common feature across many wells in Orange County, though individual wells vary.
Wells in Orange County show several contaminants that exceed EPA health standards. Arsenic, lead, uranium, and radon are radioactive or toxic metals that build up in your body over time and can cause cancer or damage your kidneys and bones. Nitrate and chloride affect how your body processes oxygen and regulates salt. Fluoride, manganese, and iron also exceed health limits in some county wells. Each of these poses different risks depending on how much is in your water and how long you drink it.
The hard water common in Orange County wells can leave white scale buildup on faucets, shower heads, and inside pipes. Hard water makes soap work less well and can leave your skin and hair feeling sticky. Over time, hard water reduces how long water heaters and dishwashers last because minerals clog them up inside. You might notice a slight metallic or earthy taste in your water.
We recommend testing your well to find out what is actually in your water, since every well is different and yours could have higher or lower levels than other county wells. A comprehensive panel testing for metals and other contaminants runs between $200 and $400. Testing is the only way to know what needs treatment, whether that is a filter, water softener, or another system. Once you know what is in your water, you can decide on the right treatment for your family.
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 | 52 | 98% | Moderate | High ⓘ | |
| Manganese | 713 | 13% | High | Moderate | |
| Iron | 563 | 10% | High | Moderate | |
| Lead | 2071 | 6% | High | Moderate | |
| Arsenic | 1220 | 3% | High | Low | |
| Chloride | 1047 | 1% | High | Low | |
| Nitrate | 1113 | 0% | High | Low | |
| Fluoride | 1293 | 0% | High | Low | |
| Uranium | 1111 | 0% | High | Low | |
| Nitrite | 1095 | 0% | High | Low | |
| Sulfate | 10 | 0% | Low | Low | |
| Total Coliform | 1* | 0% | Low | Safe ⓘ | |
| Sodium | 550 | — | High | Low | |
| pH | 192 | — | High | Low | |
| Hardness | 377 | — | High | Low | |
| E. coli | 1* | 0% | Low | 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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