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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 uranium for California water systems — Six-Year Review compliance samples 2012–2019 (historical). Methodology
These cities have uranium levels above 50% of the EPA limit but within compliance
Every California system with a uranium 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 |
|---|---|---|---|---|---|
| BurbankGrade A | 18.76 ug/LAverage of 8 samples | 2012–2019 | 30.00 ug/L | 62.5% | Warning |
| MantecaGrade B | 16.39 ug/LAverage of 1 samples | 2012–2019 | 30.00 ug/L | 54.6% | Warning |
| RiversideGrade B | 12.05 ug/LAverage of 2176 samples | 2012–2019 | 30.00 ug/L | 40.2% | Safe |
| Fountain ValleyGrade A | 9.03 ug/LAverage of 8 samples | 2012–2019 | 30.00 ug/L | 30.1% | Safe |
| ModestoGrade D | 8.77 ug/LAverage of 1831 samples | 2012–2019 | 30.00 ug/L | 29.2% | Safe |
| SalinasGrade A | 8.66 ug/LAverage of 5 samples | 2012–2019 | 30.00 ug/L | 28.9% | Safe |
| Simi ValleyGrade A | 8.31 ug/LAverage of 5 samples | 2012–2019 | 30.00 ug/L | 27.7% | Safe |
| OceansideGrade A | 5.79 ug/LAverage of 10 samples | 2012–2019 | 30.00 ug/L | 19.3% | Safe |
| Santa MonicaGrade B | 5.00 ug/LAverage of 111 samples | 2012–2019 | 30.00 ug/L | 16.7% | Safe |
| La MesaGrade A | 4.91 ug/LAverage of 6 samples | 2012–2019 | 30.00 ug/L | 16.4% | Safe |
| Los AngelesGrade A | 4.47 ug/LAverage of 80 samples | 2012–2019 | 30.00 ug/L | 14.9% | Safe |
| OxnardGrade A | 4.37 ug/LAverage of 12 samples | 2012–2019 | 30.00 ug/L | 14.6% | Safe |
| PittsburgGrade A | 3.17 ug/LAverage of 10 samples | 2012–2019 | 30.00 ug/L | 10.6% | Safe |
| IrvineGrade A | 2.66 ug/LAverage of 51 samples | 2012–2019 | 30.00 ug/L | 8.9% | Safe |
| San DiegoGrade A | 2.44 ug/LAverage of 10 samples | 2012–2019 | 30.00 ug/L | 8.1% | Safe |
| Costa MesaGrade A | 2.19 ug/LAverage of 4 samples | 2012–2019 | 30.00 ug/L | 7.3% | Safe |
| TemeculaGrade C | 2.17 ug/LAverage of 14 samples | 2012–2019 | 30.00 ug/L | 7.2% | Safe |
| Jurupa ValleyGrade A | 2.10 ug/LAverage of 3 samples | 2012–2019 | 30.00 ug/L | 7.0% | Safe |
| EncinitasGrade A | 2.07 ug/LAverage of 9 samples | 2012–2019 | 30.00 ug/L | 6.9% | Safe |
| BakersfieldGrade C | 1.89 ug/LAverage of 61 samples | 2012–2019 | 30.00 ug/L | 6.3% | Safe |
| EscondidoGrade A | 1.79 ug/LAverage of 5 samples | 2012–2019 | 30.00 ug/L | 6.0% | Safe |
| El MonteGrade A | 1.73 ug/LAverage of 5 samples | 2012–2019 | 30.00 ug/L | 5.8% | Safe |
| UplandGrade A | 1.50 ug/LAverage of 2 samples | 2012–2019 | 30.00 ug/L | 5.0% | Safe |
| PerrisGrade A | 1.33 ug/LAverage of 25 samples | 2012–2019 | 30.00 ug/L | 4.4% | Safe |
| TustinGrade B | 1.33 ug/LAverage of 2 samples | 2012–2019 | 30.00 ug/L | 4.4% | Safe |
Showing 25 of 46 cities. View individual city pages for detailed reports.
Uranium poses both chemical and radiological health risks. As a heavy metal, uranium is toxic to the kidneys and can cause kidney damage and eventual kidney failure with long-term exposure. As a radioactive element, uranium exposure increases cancer risk, particularly bone cancer due to accumulation in bones. The chemical toxicity to kidneys is the primary concern at levels found in drinking water.
Erosion of natural deposits; common in certain geologic formations, especially granite
Based on our analysis of EPA Safe Drinking Water Information System (SDWIS) data and local water utility reports,uranium has been detected in 46 California water systems. The average level across all tested cities is 10% of the EPA Maximum Contaminant Level (MCL), with the highest detection at 62.5% of the limit.
The EPA MCL for uranium is 30 micrograms per liter (30 ppb). The EPA MCL for uranium is 30 ug/L. This limit is set to protect public health based on available scientific evidence about the contaminant's health effects.
46 California cities have uranium detected in their water supply. All tested cities are within EPA safety limits.
Kidney damage and potential kidney failure, increased cancer risk. The most vulnerable groups include people with kidney disease and pregnant women.
The most effective methods for removing uranium include Reverse Osmosis, Strong Base Anion Exchange, Distillation. Look for filters certified by NSF/ANSI for uranium reduction.
The EPA Maximum Contaminant Level (MCL) for uranium is 30 ug/L.The EPA MCL for uranium is 30 micrograms per liter (30 ppb).
This page shows what California utilities reported for uranium. 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 uranium removal:
Removes 95-98% of uranium
Very effective for uranium
Effective removal
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 uranium.