What was found in ZIP 91016
The level at this ZIP's main supplier, the highest level anywhere in it, the EPA limit for each, and where the figure comes from.
| Contaminant | Level vs EPA limit | Suppliers | Source |
|---|---|---|---|
| Nitrate-Nitrite | 12000 µg/L 120% of the EPA limit, at the 95th percentile of samples — 10000 µg/L Main supplier: MONROVIA-CITY, WATER DEPT. · 37,931 people · 2017
Highest in the ZIP: 747500 µg/L — CAL-AM WATER COMPANY - DUARTE · 24,773 people · 2019 | 3/3 | SYR4 |
| Nitrate | 13000 µg/L 130% of the EPA limit, at the 95th percentile of samples — 10000 µg/L Main supplier: MONROVIA-CITY, WATER DEPT. · 37,931 people · 2019 | 3/3 | SYR4 |
| Fluoride | 462 µg/L 12% of the EPA limit 4000 µg/L Main supplier: MONROVIA-CITY, WATER DEPT. · 37,931 people · 2019
Highest in the ZIP: 853 µg/L — GSWC-SOUTH ARCADIA · 27,072 people · 2019 | 3/3 | SYR4 |
| Copper | 234 µg/L 18% of the EPA limit 1300 µg/L Highest in the ZIP: CAL-AM WATER COMPANY - DUARTE · 24,773 people · 2019 | 1/3 | SYR4 |
| Barium | 200 µg/L 10% of the EPA limit 2000 µg/L Highest in the ZIP: CAL-AM WATER COMPANY - DUARTE · 24,773 people · 2019 | 1/3 | SYR4 |
| TTHM | 19 µg/L 24% of the EPA limit 80 µg/L Main supplier: MONROVIA-CITY, WATER DEPT. · 37,931 people · 2019
Highest in the ZIP: 19.05 µg/L — CAL-AM WATER COMPANY - DUARTE · 24,773 people · 2019 | 3/3 | SYR4 |
| Trichloroethylene | 11 µg/L 220% of the EPA limit, at the 95th percentile of samples — 5 µg/L Main supplier: MONROVIA-CITY, WATER DEPT. · 37,931 people · 2019
Highest in the ZIP: 14 µg/L — GSWC-SOUTH ARCADIA · 27,072 people · 2019 | 2/3 | SYR4 |
| Bromoform | 10.9 µg/L No EPA limit set Main supplier: MONROVIA-CITY, WATER DEPT. · 37,931 people · 2019 | 3/3 | SYR4 |
| Dibromochloromethane | 7.035 µg/L No EPA limit set Main supplier: MONROVIA-CITY, WATER DEPT. · 37,931 people · 2019 | 3/3 | SYR4 |
| Tetrachloroethylene | 2.5 µg/L 50% of the EPA limit 5 µg/L Main supplier: MONROVIA-CITY, WATER DEPT. · 37,931 people · 2019
Highest in the ZIP: 6.04 µg/L — GSWC-SOUTH ARCADIA · 27,072 people · 2019 | 2/3 | SYR4 |
| Combined Uranium | 5.22245 µg/L 17% of the EPA limit 30 µg/L Main supplier: MONROVIA-CITY, WATER DEPT. · 37,931 people · 2019 | 3/3 | SYR4 |
| Dichloromethane | 3.32 µg/L 66% of the EPA limit 5 µg/L Highest in the ZIP: GSWC-SOUTH ARCADIA · 27,072 people · 2019 | 1/3 | SYR4 |
| Total Haloacetic Acids (HAA5) | 2.48 µg/L 4.1% of the EPA limit 60 µg/L Main supplier: MONROVIA-CITY, WATER DEPT. · 37,931 people · 2019
Highest in the ZIP: 3.24 µg/L — CAL-AM WATER COMPANY - DUARTE · 24,773 people · 2019 | 3/3 | SYR4 |
| Bromodichloromethane | 3 µg/L No EPA limit set Main supplier: MONROVIA-CITY, WATER DEPT. · 37,931 people · 2019
Highest in the ZIP: 3.22 µg/L — CAL-AM WATER COMPANY - DUARTE · 24,773 people · 2019 | 3/3 | SYR4 |
| Arsenic | 3.1 µg/L 31% of the EPA limit 10 µg/L Highest in the ZIP: CAL-AM WATER COMPANY - DUARTE · 24,773 people · 2019 | 1/3 | SYR4 |
| Dibromoacetic Acid | 2.48 µg/L No EPA limit set Main supplier: MONROVIA-CITY, WATER DEPT. · 37,931 people · 2019
Highest in the ZIP: 3.075 µg/L — CAL-AM WATER COMPANY - DUARTE · 24,773 people · 2019 | 3/3 | SYR4 |
| Monochloroacetic Acid | 2.59 µg/L No EPA limit set Highest in the ZIP: GSWC-SOUTH ARCADIA · 27,072 people · 2019 | 1/3 | SYR4 |
| Chloroform | 1.72 µg/L No EPA limit set Main supplier: MONROVIA-CITY, WATER DEPT. · 37,931 people · 2019
Highest in the ZIP: 1.95 µg/L — CAL-AM WATER COMPANY - DUARTE · 24,773 people · 2019 | 3/3 | SYR4 |
| Dichloroacetic Acid | 1.2 µg/L No EPA limit set Highest in the ZIP: CAL-AM WATER COMPANY - DUARTE · 24,773 people · 2019 | 1/3 | SYR4 |
| Trichloroacetic Acid | 1.2 µg/L No EPA limit set Highest in the ZIP: CAL-AM WATER COMPANY - DUARTE · 24,773 people · 2019 | 1/3 | SYR4 |
| 1,1-Dichloroethylene | 0.8450 µg/L 12% of the EPA limit 7 µg/L Main supplier: MONROVIA-CITY, WATER DEPT. · 37,931 people · 2019 | 1/3 | SYR4 |
| PFOS | 0.0061 µg/L No EPA limit set Main supplier: MONROVIA-CITY, WATER DEPT. · 37,931 people · 2025
Highest in the ZIP: 0.0220 µg/L — GSWC-SOUTH ARCADIA · 27,072 people · 2024 | 3/3 | UCMR-5 |
| Pfhxa | 0.0140 µg/L No EPA limit set Main supplier: MONROVIA-CITY, WATER DEPT. · 37,931 people · 2025 | 1/3 | UCMR-5 |
| Pfpea | 0.0097 µg/L No EPA limit set Main supplier: MONROVIA-CITY, WATER DEPT. · 37,931 people · 2025 | 1/3 | UCMR-5 |
| PFHXS | 0.0035 µg/L No EPA limit set Main supplier: MONROVIA-CITY, WATER DEPT. · 37,931 people · 2025
Highest in the ZIP: 0.0070 µg/L — GSWC-SOUTH ARCADIA · 27,072 people · 2024 | 2/3 | UCMR-5 |
| PFOA | 0.0054 µg/L No EPA limit set Main supplier: MONROVIA-CITY, WATER DEPT. · 37,931 people · 2025
Highest in the ZIP: 0.0055 µg/L — GSWC-SOUTH ARCADIA · 27,072 people · 2024 | 2/3 | UCMR-5 |
| Pfba | 0.0052 µg/L No EPA limit set Main supplier: MONROVIA-CITY, WATER DEPT. · 37,931 people · 2025 | 1/3 | UCMR-5 |
| Lead | 0.0 mg/L 0% of the EPA limit 0.0150 mg/L Main supplier: MONROVIA-CITY, WATER DEPT. · 37,931 people · 2024
Highest in the ZIP: 0.0010 mg/L — CAL-AM WATER COMPANY - DUARTE · 24,773 people · 2024 | 3/3 | 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.
Water suppliers serving ZIP 91016
| Supplier | State | Population served |
|---|---|---|
| MONROVIA-CITY, WATER DEPT. | CA | 37,931 |
| GSWC-SOUTH ARCADIA | CA | 27,072 |
| CAL-AM WATER COMPANY - DUARTE | CA | 24,773 |
Frequently asked questions about ZIP 91016 tap water
Is the tap water in ZIP 91016 safe to drink?
EPA testing detected 28 contaminants across the water suppliers serving ZIP 91016. A detection isn't the same as a violation — most levels are within federal limits. See each level and source above, and your utility's annual Consumer Confidence Report for the official status.
Which water suppliers serve ZIP 91016?
3 public water suppliers report EPA drinking-water monitoring for ZIP 91016. Each is listed above with its population served.
What contaminants are in ZIP 91016's water?
EPA monitoring detected Nitrate-Nitrite, Nitrate, Fluoride, Copper, Barium, and others across this ZIP's suppliers. The full list with levels and sources is above.