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Not health advice. Contact your local water utility for concerns.
Data from EPA Water Quality Reports. For official information, contact your water utility or health department.
Analysis of arsenic contamination levels across California cities
Complete list of cities where arsenic has been detected, sorted by level
| City | Level | EPA Limit | % of Limit | Status |
|---|---|---|---|---|
| MantecaGrade B- | 0.0049 mg/L | 0.010 mg/L | 48.7% | Safe |
| BellflowerGrade B- | 0.0046 mg/L | 0.010 mg/L | 46.3% | Safe |
| PleasantonGrade C+ | 0.0046 mg/L | 0.010 mg/L | 46.2% | Safe |
| LancasterGrade C- | 0.0045 mg/L | 0.010 mg/L | 45.0% | Safe |
| CerritosGrade C+ | 0.0045 mg/L | 0.010 mg/L | 44.9% | Safe |
| IndioGrade F | 0.0045 mg/L | 0.010 mg/L | 44.8% | Safe |
| CarlsbadGrade C+ | 0.0043 mg/L | 0.010 mg/L | 42.8% | Safe |
| Santa AnaGrade C+ | 0.0042 mg/L | 0.010 mg/L | 41.7% | Safe |
| Santa ClaraGrade D | 0.0041 mg/L | 0.010 mg/L | 41.4% | Safe |
| Lake ForestGrade C+ | 0.0040 mg/L | 0.010 mg/L | 40.0% | Safe |
| San BuenaventuraGrade F | 0.0040 mg/L | 0.010 mg/L | 40.0% | Safe |
| RedlandsGrade C | 0.0033 mg/L | 0.010 mg/L | 33.4% | Safe |
| Garden GroveGrade D | 0.0032 mg/L | 0.010 mg/L | 32.4% | Safe |
| EncinitasGrade C- | 0.0032 mg/L | 0.010 mg/L | 32.1% | Safe |
| CupertinoGrade B | 0.0030 mg/L | 0.010 mg/L | 30.0% | Safe |
| ConcordGrade C+ | 0.0029 mg/L | 0.010 mg/L | 29.1% | Safe |
| Buena ParkGrade A- | 0.0029 mg/L | 0.010 mg/L | 28.8% | Safe |
| MaderaGrade C+ | 0.0029 mg/L | 0.010 mg/L | 28.7% | Safe |
| PowayGrade C+ | 0.0029 mg/L | 0.010 mg/L | 28.6% | Safe |
| DelanoGrade C+ | 0.0028 mg/L | 0.010 mg/L | 28.3% | Safe |
| PerrisGrade C+ | 0.0028 mg/L | 0.010 mg/L | 28.2% | Safe |
| Moreno ValleyGrade C+ | 0.0028 mg/L | 0.010 mg/L | 28.0% | Safe |
| ParamountGrade B | 0.0028 mg/L | 0.010 mg/L | 27.7% | Safe |
| OaklandGrade C+ | 0.0028 mg/L | 0.010 mg/L | 27.7% | Safe |
| Jurupa ValleyGrade B- | 0.0028 mg/L | 0.010 mg/L | 27.6% | Safe |
Showing 25 of 178 cities. View individual city pages for detailed reports.
Arsenic is a known human carcinogen linked to cancers of the skin, bladder, lung, kidney, and liver. Long-term exposure can cause skin damage including color changes and lesions. Arsenic exposure is associated with cardiovascular disease, diabetes, and neurological effects. Studies have shown links between arsenic exposure and developmental effects in children, including reduced IQ and learning disabilities.
Erosion of natural deposits in the earth; runoff from orchards; discharge from glass and petroleum refineries
Based on our analysis of EPA Safe Drinking Water Information System (SDWIS) data and local water utility reports,arsenic has been detected in 178 California water systems. The average level across all tested cities is 14% of the EPA Maximum Contaminant Level (MCL), with the highest detection at 48.7% of the limit.
The EPA set the arsenic MCL at 0.010 mg/L (10 ppb) in 2001. The EPA MCL for arsenic is 0.01 mg/L. This limit is set to protect public health based on available scientific evidence about the contaminant's health effects.
178 California cities have arsenic detected in their water supply. All tested cities are within EPA safety limits.
Increased cancer risk (skin, bladder, lung), skin damage, cardiovascular disease, diabetes. The most vulnerable groups include children and people with cardiovascular conditions.
The most effective methods for removing arsenic include Reverse Osmosis, Adsorption Media (Iron-Based), Distillation. Look for filters certified by NSF/ANSI for arsenic reduction.
The EPA Maximum Contaminant Level (MCL) for arsenic is 0.01 mg/L.The EPA set the arsenic MCL at 0.010 mg/L (10 ppb) in 2001.
Recommended filtration methods for arsenic removal:
Removes 90-95% of arsenic
Specifically designed for arsenic
Effective for all forms of arsenic