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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.
Real EPA measurements of copper for California water systems — Six-Year Review compliance samples 2012–2019 (historical). Methodology
Every California system with a copper result in EPA's data, sorted by level. Averages of 2012–2019 finished-water samples, non-detects counted as zero — historical, not today's tap.
| City | Level | Period | EPA Limit | % of Limit | Status |
|---|---|---|---|---|---|
| LynwoodGrade C | 210.00 ug/LAverage of 1 samples | 2012–2019 | 1300.00 ug/L | 16.2% | Safe |
| ComptonGrade C | 170.00 ug/LAverage of 1 samples | 2012–2019 | 1300.00 ug/L | 13.1% | Safe |
| San MateoGrade A | 125.19 ug/LAverage of 7 samples | 2012–2019 | 1300.00 ug/L | 9.6% | Safe |
| Simi ValleyGrade A | 30.20 ug/LAverage of 5 samples | 2012–2019 | 1300.00 ug/L | 2.3% | Safe |
| Lake ElsinoreGrade A | 13.47 ug/LAverage of 19 samples | 2012–2019 | 1300.00 ug/L | 1.0% | Safe |
| LivermoreGrade D | 6.34 ug/LAverage of 1 samples | 2012–2019 | 1300.00 ug/L | 0.5% | Safe |
| Jurupa ValleyGrade A | 5.12 ug/LAverage of 68 samples | 2012–2019 | 1300.00 ug/L | 0.4% | Safe |
| FremontGrade A | 4.30 ug/LAverage of 135 samples | 2012–2019 | 1300.00 ug/L | 0.3% | Safe |
| BakersfieldGrade C | 3.19 ug/LAverage of 92 samples | 2012–2019 | 1300.00 ug/L | 0.2% | Safe |
| Los AngelesGrade A | 1.40 ug/LAverage of 97 samples | 2012–2019 | 1300.00 ug/L | 0.1% | Safe |
| FairfieldGrade D | 1.18 ug/LAverage of 62 samples | 2012–2019 | 1300.00 ug/L | 0.1% | Safe |
| OaklandGrade A | 0 ug/LAverage of 457 samples | 2012–2019 | 1300.00 ug/L | 0.0% | Safe |
| San DiegoGrade A | 0 ug/LAverage of 279 samples | 2012–2019 | 1300.00 ug/L | 0.0% | Safe |
| San JoseGrade C | 0 ug/LAverage of 15 samples | 2012–2019 | 1300.00 ug/L | 0.0% | Safe |
| PerrisGrade A | 0.504 ug/LAverage of 26 samples | 2012–2019 | 1300.00 ug/L | 0.0% | Safe |
| FresnoGrade C | 0 ug/LAverage of 5 samples | 2012–2019 | 1300.00 ug/L | 0.0% | Safe |
| SacramentoGrade C | 0 ug/LAverage of 16 samples | 2012–2019 | 1300.00 ug/L | 0.0% | Safe |
| IrvineGrade A | 0 ug/LAverage of 23 samples | 2012–2019 | 1300.00 ug/L | 0.0% | Safe |
| RiversideGrade B | 0.174 ug/LAverage of 317 samples | 2012–2019 | 1300.00 ug/L | 0.0% | Safe |
| La MesaGrade A | 0 ug/LAverage of 11 samples | 2012–2019 | 1300.00 ug/L | 0.0% | Safe |
| Palm DesertGrade A | 0 ug/LAverage of 7 samples | 2012–2019 | 1300.00 ug/L | 0.0% | Safe |
| El MonteGrade A | 0 ug/LAverage of 3 samples | 2012–2019 | 1300.00 ug/L | 0.0% | Safe |
| FontanaGrade A | 0 ug/LAverage of 8 samples | 2012–2019 | 1300.00 ug/L | 0.0% | Safe |
| ModestoGrade D | 0 ug/LAverage of 2 samples | 2012–2019 | 1300.00 ug/L | 0.0% | Safe |
| OxnardGrade A | 0 ug/LAverage of 16 samples | 2012–2019 | 1300.00 ug/L | 0.0% | Safe |
Showing 25 of 74 cities. View individual city pages for detailed reports.
Copper is essential in small amounts, but elevated levels can cause gastrointestinal distress including nausea, vomiting, and diarrhea. Long-term exposure can cause liver or kidney damage. People with Wilson's disease are particularly vulnerable. Very high levels can give water a blue-green color and metallic taste.
Corrosion of household plumbing systems; erosion of natural deposits; copper pipes
Based on our analysis of EPA Safe Drinking Water Information System (SDWIS) data and local water utility reports,copper has been detected in 74 California water systems. The average level across all tested cities is 1% of the EPA Maximum Contaminant Level (MCL), with the highest detection at 16.2% of the limit.
The EPA action level for copper is 1.3 mg/L. The EPA MCL for copper is 1.3 mg/L. This limit is set to protect public health based on available scientific evidence about the contaminant's health effects.
74 California cities have copper detected in their water supply. All tested cities are within EPA safety limits.
Gastrointestinal distress, liver and kidney damage with long-term exposure. The most vulnerable groups include people with wilson's disease and infants under 1 year.
The most effective methods for removing copper include Reverse Osmosis, Distillation, Ion Exchange. Look for filters certified by NSF/ANSI for copper reduction.
The EPA Maximum Contaminant Level (MCL) for copper is 1.3 mg/L.The EPA action level for copper is 1.3 mg/L.
This page shows what California utilities reported for copper. It cannot tell you what is coming out of your own tap: utility samples are taken across a whole system and averaged, levels vary by address and season, and anything picked up after the water leaves the main never appears in their report.
Home water test kitscheck your own tap before buying any filterRecommended filtration methods for copper removal:
Removes 97-98% of copper
Very effective
Water softeners can help
Paid links. We earn a commission if you buy, at no extra cost to you. Filters are matched to the removal methods listed above for copper.