What was found in ZIP 91724
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 | 10780 µg/L 108% of the EPA limit, at the 95th percentile of samples — 10000 µg/L Highest in the ZIP: VALENCIA HEIGHTS WATER CO. · 7,775 people · 2019 | 1/3 | SYR4 |
| Nitrate | 10000 µg/L 100% of the EPA limit 10000 µg/L Highest in the ZIP: VALENCIA HEIGHTS WATER CO. · 7,775 people · 2019 | 1/3 | SYR4 |
| Fluoride | 477.5 µg/L 12% of the EPA limit 4000 µg/L Highest in the ZIP: VALENCIA HEIGHTS WATER CO. · 7,775 people · 2019 | 1/3 | SYR4 |
| Barium | 146 µg/L 7.3% of the EPA limit 2000 µg/L Highest in the ZIP: VALENCIA HEIGHTS WATER CO. · 7,775 people · 2019 | 1/3 | SYR4 |
| TTHM | 59.65 µg/L 75% of the EPA limit 80 µg/L Main supplier: GSWC-SAN DIMAS · 56,538 people · 2019
Highest in the ZIP: 81.35 µg/L — COVINA-CITY, WATER DEPT. · 33,300 people · 2019 | 3/3 | SYR4 |
| Lithium | 57 µg/L No EPA limit set Main supplier: GSWC-SAN DIMAS · 56,538 people · 2025 | 3/3 | UCMR-5 |
| Chloroform | 23 µg/L No EPA limit set Main supplier: GSWC-SAN DIMAS · 56,538 people · 2019
Highest in the ZIP: 42 µg/L — COVINA-CITY, WATER DEPT. · 33,300 people · 2019 | 3/3 | SYR4 |
| Total Haloacetic Acids (HAA5) | 23 µg/L 38% of the EPA limit 60 µg/L Main supplier: GSWC-SAN DIMAS · 56,538 people · 2019
Highest in the ZIP: 35.4 µg/L — COVINA-CITY, WATER DEPT. · 33,300 people · 2019 | 3/3 | SYR4 |
| Dibromochloromethane | 22 µg/L No EPA limit set Main supplier: GSWC-SAN DIMAS · 56,538 people · 2019
Highest in the ZIP: 29.8 µg/L — COVINA-CITY, WATER DEPT. · 33,300 people · 2019 | 3/3 | SYR4 |
| Bromoform | 12 µg/L No EPA limit set Main supplier: GSWC-SAN DIMAS · 56,538 people · 2019
Highest in the ZIP: 25 µg/L — VALENCIA HEIGHTS WATER CO. · 7,775 people · 2019 | 3/3 | SYR4 |
| Combined Uranium | 23.84 µg/L 79% of the EPA limit 30 µg/L Highest in the ZIP: VALENCIA HEIGHTS WATER CO. · 7,775 people · 2019 | 1/3 | SYR4 |
| Dichloroacetic Acid | 12 µg/L No EPA limit set Main supplier: GSWC-SAN DIMAS · 56,538 people · 2019
Highest in the ZIP: 23 µg/L — COVINA-CITY, WATER DEPT. · 33,300 people · 2019 | 3/3 | SYR4 |
| Di(2-ethylhexyl) Phthalate | 22 µg/L 367% of the EPA limit, at the 95th percentile of samples — 6 µg/L Highest in the ZIP: VALENCIA HEIGHTS WATER CO. · 7,775 people · 2018 | 1/3 | SYR4 |
| Bromodichloromethane | 20 µg/L No EPA limit set Main supplier: GSWC-SAN DIMAS · 56,538 people · 2019 | 3/3 | SYR4 |
| Trichloroacetic Acid | 8.845 µg/L No EPA limit set Main supplier: GSWC-SAN DIMAS · 56,538 people · 2019
Highest in the ZIP: 17.4 µg/L — COVINA-CITY, WATER DEPT. · 33,300 people · 2019 | 3/3 | SYR4 |
| Dibromoacetic Acid | 7.405 µg/L No EPA limit set Main supplier: GSWC-SAN DIMAS · 56,538 people · 2019
Highest in the ZIP: 10.2 µg/L — COVINA-CITY, WATER DEPT. · 33,300 people · 2019 | 3/3 | SYR4 |
| Monobromoacetic Acid | 6.7 µg/L No EPA limit set Highest in the ZIP: COVINA-CITY, WATER DEPT. · 33,300 people · 2019 | 1/3 | SYR4 |
| Selenium | 5.2 µg/L 10% of the EPA limit 50 µg/L Highest in the ZIP: VALENCIA HEIGHTS WATER CO. · 7,775 people · 2019 | 1/3 | SYR4 |
| PFOA | 0.0057 µg/L No EPA limit set Highest in the ZIP: VALENCIA HEIGHTS WATER CO. · 7,775 people · 2024 | 1/3 | UCMR-5 |
| PFOS | 0.0045 µg/L No EPA limit set Main supplier: GSWC-SAN DIMAS · 56,538 people · 2025 | 2/3 | UCMR-5 |
| PFBS | 0.0044 µg/L No EPA limit set Highest in the ZIP: VALENCIA HEIGHTS WATER CO. · 7,775 people · 2024 | 1/3 | UCMR-5 |
| Pfhxa | 0.0043 µg/L No EPA limit set Highest in the ZIP: VALENCIA HEIGHTS WATER CO. · 7,775 people · 2024 | 1/3 | UCMR-5 |
| Pfpea | 0.0040 µg/L No EPA limit set Highest in the ZIP: VALENCIA HEIGHTS WATER CO. · 7,775 people · 2024 | 1/3 | UCMR-5 |
| PFHXS | 0.0036 µg/L No EPA limit set Highest in the ZIP: VALENCIA HEIGHTS WATER CO. · 7,775 people · 2024 | 1/3 | UCMR-5 |
| Lead | 0.0021 mg/L 14% of the EPA limit 0.0150 mg/L Main supplier: GSWC-SAN DIMAS · 56,538 people · 2026 | 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 91724
| Supplier | State | Population served |
|---|---|---|
| GSWC-SAN DIMAS | CA | 56,538 |
| COVINA-CITY, WATER DEPT. | CA | 33,300 |
| VALENCIA HEIGHTS WATER CO. | CA | 7,775 |
Frequently asked questions about ZIP 91724 tap water
Is the tap water in ZIP 91724 safe to drink?
EPA testing detected 25 contaminants across the water suppliers serving ZIP 91724. 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 91724?
3 public water suppliers report EPA drinking-water monitoring for ZIP 91724. Each is listed above with its population served.
What contaminants are in ZIP 91724's water?
EPA monitoring detected Nitrate-Nitrite, Nitrate, Fluoride, Barium, TTHM, and others across this ZIP's suppliers. The full list with levels and sources is above.