What was found in ZIP 78504
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 |
|---|---|---|---|
| Fluoride | 750 µg/L 19% of the EPA limit 4000 µg/L Main supplier: MCALLEN PUBLIC UTILITY · 189,957 people · 2019 | 2/2 | SYR4 |
| Chlorite | 700 µg/L 70% of the EPA limit 1000 µg/L Main supplier: MCALLEN PUBLIC UTILITY · 189,957 people · 2019 | 2/2 | SYR4 |
| Nitrate | 307.5 µg/L 3.1% of the EPA limit 10000 µg/L Main supplier: MCALLEN PUBLIC UTILITY · 189,957 people · 2019
Highest in the ZIP: 460 µg/L — SHARYLAND WSC · 68,562 people · 2019 | 2/2 | SYR4 |
| Cyanide | 148 µg/L 74% of the EPA limit 200 µg/L Main supplier: MCALLEN PUBLIC UTILITY · 189,957 people · 2019 | 2/2 | SYR4 |
| Copper | 140.7 µg/L 11% of the EPA limit 1300 µg/L Main supplier: MCALLEN PUBLIC UTILITY · 189,957 people · 2018 | 2/2 | SYR4 |
| Barium | 119 µg/L 5.9% of the EPA limit 2000 µg/L Main supplier: MCALLEN PUBLIC UTILITY · 189,957 people · 2019
Highest in the ZIP: 120 µg/L — SHARYLAND WSC · 68,562 people · 2019 | 2/2 | SYR4 |
| TTHM | 79.14 µg/L 99% of the EPA limit 80 µg/L Main supplier: MCALLEN PUBLIC UTILITY · 189,957 people · 2019 | 2/2 | SYR4 |
| Lithium | 51.8 µg/L No EPA limit set Main supplier: MCALLEN PUBLIC UTILITY · 189,957 people · 2024 | 2/2 | UCMR-5 |
| Bromoform | 37.15 µg/L No EPA limit set Main supplier: MCALLEN PUBLIC UTILITY · 189,957 people · 2019 | 2/2 | SYR4 |
| Dibromochloromethane | 26.465 µg/L No EPA limit set Main supplier: MCALLEN PUBLIC UTILITY · 189,957 people · 2019 | 2/2 | SYR4 |
| Total Haloacetic Acids (HAA5) | 26 µg/L 43% of the EPA limit 60 µg/L Main supplier: MCALLEN PUBLIC UTILITY · 189,957 people · 2019 | 2/2 | SYR4 |
| Dibromoacetic Acid | 18.28 µg/L No EPA limit set Main supplier: MCALLEN PUBLIC UTILITY · 189,957 people · 2019 | 2/2 | SYR4 |
| Monochloroacetic Acid | 9.325 µg/L No EPA limit set Main supplier: MCALLEN PUBLIC UTILITY · 189,957 people · 2019
Highest in the ZIP: 13.78 µg/L — SHARYLAND WSC · 68,562 people · 2019 | 2/2 | SYR4 |
| Bromodichloromethane | 8.6 µg/L No EPA limit set Main supplier: MCALLEN PUBLIC UTILITY · 189,957 people · 2019 | 2/2 | SYR4 |
| Gross Beta Particle Activity | 6.1 pCi/L No EPA limit set Main supplier: MCALLEN PUBLIC UTILITY · 189,957 people · 2018
Highest in the ZIP: 7.9 pCi/L — SHARYLAND WSC · 68,562 people · 2019 | 2/2 | SYR4 |
| Monobromoacetic Acid | 6.84 µg/L No EPA limit set Main supplier: MCALLEN PUBLIC UTILITY · 189,957 people · 2019 | 2/2 | SYR4 |
| Dichloroacetic Acid | 4.7 µg/L No EPA limit set Main supplier: MCALLEN PUBLIC UTILITY · 189,957 people · 2019
Highest in the ZIP: 6.69 µg/L — SHARYLAND WSC · 68,562 people · 2019 | 2/2 | SYR4 |
| Selenium | 6.66 µg/L 13% of the EPA limit 50 µg/L Main supplier: MCALLEN PUBLIC UTILITY · 189,957 people · 2019 | 2/2 | SYR4 |
| Lead | 4.7065 µg/L 31% of the EPA limit 15 µg/L Main supplier: MCALLEN PUBLIC UTILITY · 189,957 people · 2018
Highest in the ZIP: 6.17 µg/L — SHARYLAND WSC · 68,562 people · 2018 | 2/2 | SYR4 |
| Chloroform | 4.2 µg/L No EPA limit set Main supplier: MCALLEN PUBLIC UTILITY · 189,957 people · 2019 | 2/2 | SYR4 |
| Gross Alpha, Excl. Radon And U | 3.7 pCi/L 25% of the EPA limit 15 pCi/L Main supplier: MCALLEN PUBLIC UTILITY · 189,957 people · 2018 | 2/2 | SYR4 |
| Trichloroacetic Acid | 3.385 µg/L No EPA limit set Main supplier: MCALLEN PUBLIC UTILITY · 189,957 people · 2019 | 2/2 | SYR4 |
| Arsenic | 3.23 µg/L 32% of the EPA limit 10 µg/L Main supplier: MCALLEN PUBLIC UTILITY · 189,957 people · 2019 | 2/2 | SYR4 |
| Combined Radium (-226 And -228) | 2.9 pCi/L 58% of the EPA limit 5 pCi/L Main supplier: MCALLEN PUBLIC UTILITY · 189,957 people · 2017 | 1/2 | SYR4 |
| Combined Uranium | 2.625 µg/L 8.8% of the EPA limit 30 µg/L Main supplier: MCALLEN PUBLIC UTILITY · 189,957 people · 2018
Highest in the ZIP: 2.785 µg/L — SHARYLAND WSC · 68,562 people · 2019 | 2/2 | SYR4 |
| Di(2-ethylhexyl) Phthalate | 2 µg/L 33% of the EPA limit 6 µg/L Main supplier: MCALLEN PUBLIC UTILITY · 189,957 people · 2019 | 1/2 | SYR4 |
| Carbon Tetrachloride | 1 µg/L 20% of the EPA limit 5 µg/L Main supplier: MCALLEN PUBLIC UTILITY · 189,957 people · 2019 | 1/2 | SYR4 |
| Antimony, Total | 0.5920 µg/L 9.9% of the EPA limit 6 µg/L Main supplier: MCALLEN PUBLIC UTILITY · 189,957 people · 2019 | 1/2 | SYR4 |
| Chromium | 0.4120 µg/L 0.4% of the EPA limit 100 µg/L Main supplier: MCALLEN PUBLIC UTILITY · 189,957 people · 2019 | 1/2 | SYR4 |
| Methoxychlor | 0.2000 µg/L 0.5% of the EPA limit 40 µg/L Main supplier: MCALLEN PUBLIC UTILITY · 189,957 people · 2019 | 1/2 | SYR4 |
| Pfba | 0.0272 µg/L No EPA limit set Main supplier: MCALLEN PUBLIC UTILITY · 189,957 people · 2024 | 2/2 | UCMR-5 |
| Pfhxa | 0.0125 µg/L No EPA limit set Highest in the ZIP: SHARYLAND WSC · 68,562 people · 2025 | 1/2 | UCMR-5 |
| Pfpea | 0.0123 µg/L No EPA limit set Highest in the ZIP: SHARYLAND WSC · 68,562 people · 2025 | 1/2 | UCMR-5 |
| Thallium, Total | 0.0090 µg/L 0.5% of the EPA limit 2 µg/L Main supplier: MCALLEN PUBLIC UTILITY · 189,957 people · 2019 | 1/2 | SYR4 |
| PFOS | 0.0068 µg/L No EPA limit set Highest in the ZIP: SHARYLAND WSC · 68,562 people · 2025 | 1/2 | UCMR-5 |
| PFHXS | 0.0064 µg/L No EPA limit set Highest in the ZIP: SHARYLAND WSC · 68,562 people · 2025 | 1/2 | UCMR-5 |
| Pfhpa | 0.0045 µg/L No EPA limit set Highest in the ZIP: SHARYLAND WSC · 68,562 people · 2025 | 1/2 | UCMR-5 |
| PFOA | 0.0043 µg/L No EPA limit set Highest in the ZIP: SHARYLAND WSC · 68,562 people · 2025 | 1/2 | UCMR-5 |
| PFBS | 0.0030 µg/L No EPA limit set Highest in the ZIP: SHARYLAND WSC · 68,562 people · 2025 | 1/2 | UCMR-5 |
| Lead | 0.0023 mg/L 15% of the EPA limit 0.0150 mg/L Main supplier: MCALLEN PUBLIC UTILITY · 189,957 people · 2024 | 2/2 | 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 78504
| Supplier | State | Population served |
|---|---|---|
| MCALLEN PUBLIC UTILITY | TX | 189,957 |
| SHARYLAND WSC | TX | 68,562 |
Frequently asked questions about ZIP 78504 tap water
Is the tap water in ZIP 78504 safe to drink?
EPA testing detected 40 contaminants across the water suppliers serving ZIP 78504. 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 78504?
2 public water suppliers report EPA drinking-water monitoring for ZIP 78504. Each is listed above with its population served.
What contaminants are in ZIP 78504's water?
EPA monitoring detected Fluoride, Chlorite, Nitrate, Cyanide, Copper, and others across this ZIP's suppliers. The full list with levels and sources is above.