What was found in Rosemead's water
The level at the city's main supplier, the highest level anywhere in the city, the EPA limit for each, and where every figure comes from.
| Contaminant | Level vs EPA limit | Suppliers | Source |
|---|---|---|---|
| Nitrate-Nitrite | 15000 µg/L 150% of the EPA limit, at the 95th percentile of samples — 10000 µg/L Main supplier: CAL/AM WATER COMPANY - SAN MARINO · 47,995 people · 2019
Highest in the city: 772500 µg/L — CAL-AM WATER COMPANY - EAST PASADENA · 9,949 people · 2018 | 6/8 | SYR4 |
| Nitrate | 10353.1 µg/L 104% of the EPA limit, at the 95th percentile of samples — 10000 µg/L Main supplier: CAL/AM WATER COMPANY - SAN MARINO · 47,995 people · 2019 | 8/8 | SYR4 |
| Fluoride | 990 µg/L 25% of the EPA limit 4000 µg/L Main supplier: CAL/AM WATER COMPANY - SAN MARINO · 47,995 people · 2019
Highest in the city: 1700 µg/L — SAN GABRIEL COUNTY WD · 39,345 people · 2019 | 8/8 | SYR4 |
| Copper | 153.3 µg/L 12% of the EPA limit 1300 µg/L Main supplier: CAL/AM WATER COMPANY - SAN MARINO · 47,995 people · 2019
Highest in the city: 234 µg/L — CAL-AM WATER COMPANY - DUARTE · 24,773 people · 2019 | 3/8 | SYR4 |
| Barium | 200 µg/L 10% of the EPA limit 2000 µg/L Highest in the city: CAL-AM WATER COMPANY - DUARTE · 24,773 people · 2019 | 4/8 | SYR4 |
| Lithium | 91.9 µg/L No EPA limit set Main supplier: CAL/AM WATER COMPANY - SAN MARINO · 47,995 people · 2025 | 2/8 | UCMR-5 |
| TTHM | 24.6 µg/L 31% of the EPA limit 80 µg/L Main supplier: CAL/AM WATER COMPANY - SAN MARINO · 47,995 people · 2019
Highest in the city: 44.425 µg/L — BELLFLOWER MUNICIPAL WATER SYSTEM · 5,999 people · 2019 | 7/8 | SYR4 |
| Carbon Tetrachloride | 0.8000 µg/L 16% of the EPA limit 5 µg/L Main supplier: CAL/AM WATER COMPANY - SAN MARINO · 47,995 people · 2019
Highest in the city: 40 µg/L — GOLDEN SANDS MOBILE HOME PARK · 450 people · 2019 | 2/8 | SYR4 |
| Combined Uranium | 14.2444 µg/L 47% of the EPA limit 30 µg/L Main supplier: CAL/AM WATER COMPANY - SAN MARINO · 47,995 people · 2019
Highest in the city: 35.164 µg/L — CAL-AM WATER COMPANY - EAST PASADENA · 9,949 people · 2019 | 8/8 | SYR4 |
| Bromoform | 4.89 µg/L No EPA limit set Main supplier: CAL/AM WATER COMPANY - SAN MARINO · 47,995 people · 2019
Highest in the city: 20.8 µg/L — CAL/AM WATER COMPANY - BALDWIN HILLS · 20,724 people · 2019 | 7/8 | SYR4 |
| Total Haloacetic Acids (HAA5) | 20 µg/L 33% of the EPA limit 60 µg/L Main supplier: CAL/AM WATER COMPANY - SAN MARINO · 47,995 people · 2019
Highest in the city: 20.12 µg/L — BELLFLOWER MUNICIPAL WATER SYSTEM · 5,999 people · 2019 | 6/8 | SYR4 |
| Chromium | 18.4 µg/L 18% of the EPA limit 100 µg/L Main supplier: CAL/AM WATER COMPANY - SAN MARINO · 47,995 people · 2019 | 4/8 | SYR4 |
| Bromodichloromethane | 12.645 µg/L No EPA limit set Main supplier: CAL/AM WATER COMPANY - SAN MARINO · 47,995 people · 2019
Highest in the city: 16.025 µg/L — BELLFLOWER MUNICIPAL WATER SYSTEM · 5,999 people · 2019 | 6/8 | SYR4 |
| Dibromochloromethane | 11.46 µg/L No EPA limit set Main supplier: CAL/AM WATER COMPANY - SAN MARINO · 47,995 people · 2019
Highest in the city: 15.22 µg/L — BELLFLOWER MUNICIPAL WATER SYSTEM · 5,999 people · 2019 | 6/8 | SYR4 |
| Chloroform | 12.88 µg/L No EPA limit set Main supplier: CAL/AM WATER COMPANY - SAN MARINO · 47,995 people · 2019
Highest in the city: 14.34 µg/L — BELLFLOWER MUNICIPAL WATER SYSTEM · 5,999 people · 2019 | 5/8 | SYR4 |
| Trichloroethylene | 2.8 µg/L 56% of the EPA limit 5 µg/L Main supplier: CAL/AM WATER COMPANY - SAN MARINO · 47,995 people · 2019
Highest in the city: 13.65 µg/L — CAL/AM WATER COMPANY - BALDWIN HILLS · 20,724 people · 2019 | 5/8 | SYR4 |
| Dichloroacetic Acid | 9.95 µg/L No EPA limit set Main supplier: CAL/AM WATER COMPANY - SAN MARINO · 47,995 people · 2019 | 4/8 | SYR4 |
| Trichloroacetic Acid | 9.855 µg/L No EPA limit set Main supplier: CAL/AM WATER COMPANY - SAN MARINO · 47,995 people · 2019 | 4/8 | SYR4 |
| Lead | 1 µg/L 6.7% of the EPA limit 15 µg/L Main supplier: CAL/AM WATER COMPANY - SAN MARINO · 47,995 people · 2019
Highest in the city: 8 µg/L — CAL/AM WATER COMPANY - BALDWIN HILLS · 20,724 people · 2019 | 2/8 | SYR4 |
| Dibromoacetic Acid | 4.41 µg/L No EPA limit set Main supplier: CAL/AM WATER COMPANY - SAN MARINO · 47,995 people · 2019
Highest in the city: 7.435 µg/L — CAL/AM WATER COMPANY - BALDWIN HILLS · 20,724 people · 2019 | 6/8 | SYR4 |
| Selenium | 6.7 µg/L 13% of the EPA limit 50 µg/L Highest in the city: GOLDEN SANDS MOBILE HOME PARK · 450 people · 2018 | 1/8 | SYR4 |
| Tetrachloroethylene | 6.5 µg/L 130% of the EPA limit, at the 95th percentile of samples — 5 µg/L Main supplier: CAL/AM WATER COMPANY - SAN MARINO · 47,995 people · 2019 | 4/8 | SYR4 |
| Arsenic | 2.9 µg/L 29% of the EPA limit 10 µg/L Main supplier: CAL/AM WATER COMPANY - SAN MARINO · 47,995 people · 2019
Highest in the city: 5.8 µg/L — GOLDEN SANDS MOBILE HOME PARK · 450 people · 2018 | 5/8 | SYR4 |
| Monochloroacetic Acid | 3 µg/L No EPA limit set Main supplier: CAL/AM WATER COMPANY - SAN MARINO · 47,995 people · 2019
Highest in the city: 5.78 µg/L — CAL/AM WATER COMPANY - BALDWIN HILLS · 20,724 people · 2019 | 2/8 | SYR4 |
| Gross Beta Particle Activity | 4.575 pCi/L No EPA limit set Highest in the city: CAL/AM WATER COMPANY - BALDWIN HILLS · 20,724 people · 2019 | 1/8 | SYR4 |
| 1,2-Dichloropropane | 2.77 µg/L 55% of the EPA limit 5 µg/L Main supplier: CAL/AM WATER COMPANY - SAN MARINO · 47,995 people · 2019 | 1/8 | SYR4 |
| Monobromoacetic Acid | 2.35 µg/L No EPA limit set Highest in the city: CAL/AM WATER COMPANY - BALDWIN HILLS · 20,724 people · 2019 | 1/8 | SYR4 |
| Mercury | 2.01 µg/L 100% of the EPA limit, at the 95th percentile of samples — 2 µg/L Main supplier: CAL/AM WATER COMPANY - SAN MARINO · 47,995 people · 2019 | 1/8 | SYR4 |
| 1,1-Dichloroethylene | 1.3 µg/L 19% of the EPA limit 7 µg/L Highest in the city: CAL-AM WATER COMPANY - EAST PASADENA · 9,949 people · 2019 | 1/8 | SYR4 |
| cis-1,2-Dichloroethylene | 1.04 µg/L 1.5% of the EPA limit 70 µg/L Main supplier: CAL/AM WATER COMPANY - SAN MARINO · 47,995 people · 2019 | 1/8 | SYR4 |
| trans-1,2-Dichloroethylene | 0.5300 µg/L 0.5% of the EPA limit 100 µg/L Highest in the city: CAL-AM WATER COMPANY - EAST PASADENA · 9,949 people · 2019 | 1/8 | SYR4 |
| PFOS | 0.0326 µg/L No EPA limit set Highest in the city: BELLFLOWER MUNICIPAL WATER SYSTEM · 5,999 people · 2025 | 2/8 | UCMR-5 |
| PFOA | 0.0076 µg/L No EPA limit set Highest in the city: BELLFLOWER MUNICIPAL WATER SYSTEM · 5,999 people · 2025 | 1/8 | UCMR-5 |
| PFHXS | 0.0056 µg/L No EPA limit set Highest in the city: BELLFLOWER MUNICIPAL WATER SYSTEM · 5,999 people · 2025 | 1/8 | UCMR-5 |
| Pfba | 0.0053 µg/L No EPA limit set Main supplier: CAL/AM WATER COMPANY - SAN MARINO · 47,995 people · 2025 | 2/8 | UCMR-5 |
| Lead | 0.0 mg/L 0% of the EPA limit 0.0150 mg/L Main supplier: CAL/AM WATER COMPANY - SAN MARINO · 47,995 people · 2023
Highest in the city: 0.0030 mg/L — CAL/AM WATER COMPANY - BALDWIN HILLS · 20,724 people · 2026 | 8/8 | LCR |
Each bar shows the measured level as a share of the EPA limit: green is
well under, amber is close to it, red is over. For lead and copper the
limit applies to exactly the 90th-percentile figure shown, so red there
means a real exceedance. For everything else the limit applies to a
running annual average while the figure is the 95th percentile of the
system's samples — over 100% is worth reading, but is not by itself a
violation.
Formal violations are listed separately.
These are the utilities' own EPA-reported results, not a city-wide
average. A detection means the lab measured the
substance — it isn't the same as exceeding a legal limit. Hover a source
tag to see the EPA program and years behind each figure.
Water suppliers serving Rosemead
| Supplier | Population served |
|---|---|
| CAL/AM WATER COMPANY - SAN MARINO | 47,995 |
| SAN GABRIEL COUNTY WD | 39,345 |
| CAL-AM WATER COMPANY - DUARTE | 24,773 |
| CAL/AM WATER COMPANY - BALDWIN HILLS | 20,724 |
| CAL-AM WATER COMPANY - EAST PASADENA | 9,949 |
| BELLFLOWER MUNICIPAL WATER SYSTEM | 5,999 |
| AMARILLO MUTUAL WATER COMPANY | 3,134 |
| GOLDEN SANDS MOBILE HOME PARK | 450 |
Frequently asked questions about Rosemead tap water
Is Rosemead tap water safe to drink?
EPA testing detected 36 contaminants in the water serving Rosemead. A detection isn't the same as a violation — most detected levels are within federal limits. Check the level and source for each contaminant above, and your utility's annual Consumer Confidence Report for the official compliance status.
How many water suppliers serve Rosemead?
8 public water suppliers report drinking-water monitoring for Rosemead, California to the EPA. Each is listed above with its population served.
What contaminants are in Rosemead's water?
The contaminants EPA monitoring detected in Rosemead include Nitrate-Nitrite, Nitrate, Fluoride, Copper, Barium. The full list, with the level at the main supplier and the data source, is in the table above.
Where does this data come from?
Every figure is official EPA drinking-water monitoring — the Lead & Copper Rule, the UCMR-5 nationwide testing program, and the EPA Six-Year Review — not our own testing. Each number is labelled with its source and period.