What was found in ZIP 78520
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 |
|---|---|---|---|
| Chlorite | 572 µg/L 57% of the EPA limit 1000 µg/L Main supplier: BROWNSVILLE PUBLIC UTILITIES BOARD · 201,249 people · 2019
Highest in the ZIP: 812.2 µg/L — OLMITO WSC · 8,952 people · 2014 | 2/2 | SYR4 |
| Nitrate | 787.5 µg/L 7.9% of the EPA limit 10000 µg/L Main supplier: BROWNSVILLE PUBLIC UTILITIES BOARD · 201,249 people · 2019 | 2/2 | SYR4 |
| Fluoride | 602.5 µg/L 15% of the EPA limit 4000 µg/L Main supplier: BROWNSVILLE PUBLIC UTILITIES BOARD · 201,249 people · 2019 | 2/2 | SYR4 |
| Copper | 319.7 µg/L 25% of the EPA limit 1300 µg/L Main supplier: BROWNSVILLE PUBLIC UTILITIES BOARD · 201,249 people · 2018 | 2/2 | SYR4 |
| Barium | 118.15 µg/L 5.9% of the EPA limit 2000 µg/L Main supplier: BROWNSVILLE PUBLIC UTILITIES BOARD · 201,249 people · 2019
Highest in the ZIP: 190.1 µg/L — OLMITO WSC · 8,952 people · 2019 | 2/2 | SYR4 |
| Cyanide | 153.5 µg/L 77% of the EPA limit 200 µg/L Main supplier: BROWNSVILLE PUBLIC UTILITIES BOARD · 201,249 people · 2019 | 2/2 | SYR4 |
| TTHM | 61.92 µg/L 77% of the EPA limit 80 µg/L Main supplier: BROWNSVILLE PUBLIC UTILITIES BOARD · 201,249 people · 2019
Highest in the ZIP: 77.28 µg/L — OLMITO WSC · 8,952 people · 2019 | 2/2 | SYR4 |
| Lithium | 51.1 µg/L No EPA limit set Main supplier: BROWNSVILLE PUBLIC UTILITIES BOARD · 201,249 people · 2025
Highest in the ZIP: 77 µg/L — OLMITO WSC · 8,952 people · 2024 | 2/2 | UCMR-5 |
| Nitrite | 57.5 µg/L 5.8% of the EPA limit 1000 µg/L Main supplier: BROWNSVILLE PUBLIC UTILITIES BOARD · 201,249 people · 2013 | 1/2 | SYR4 |
| Total Haloacetic Acids (HAA5) | 21.06 µg/L 35% of the EPA limit 60 µg/L Main supplier: BROWNSVILLE PUBLIC UTILITIES BOARD · 201,249 people · 2019
Highest in the ZIP: 34.725 µg/L — OLMITO WSC · 8,952 people · 2019 | 2/2 | SYR4 |
| Monobromoacetic Acid | 8.15 µg/L No EPA limit set Main supplier: BROWNSVILLE PUBLIC UTILITIES BOARD · 201,249 people · 2019
Highest in the ZIP: 30.12 µg/L — OLMITO WSC · 8,952 people · 2019 | 2/2 | SYR4 |
| Bromodichloromethane | 14.1 µg/L No EPA limit set Main supplier: BROWNSVILLE PUBLIC UTILITIES BOARD · 201,249 people · 2019
Highest in the ZIP: 27.295 µg/L — OLMITO WSC · 8,952 people · 2019 | 2/2 | SYR4 |
| Dibromochloromethane | 19.6 µg/L No EPA limit set Main supplier: BROWNSVILLE PUBLIC UTILITIES BOARD · 201,249 people · 2019
Highest in the ZIP: 25.47 µg/L — OLMITO WSC · 8,952 people · 2019 | 2/2 | SYR4 |
| Bromoform | 18.9 µg/L No EPA limit set Main supplier: BROWNSVILLE PUBLIC UTILITIES BOARD · 201,249 people · 2019
Highest in the ZIP: 22.08 µg/L — OLMITO WSC · 8,952 people · 2019 | 2/2 | SYR4 |
| Chloroform | 8.7 µg/L No EPA limit set Main supplier: BROWNSVILLE PUBLIC UTILITIES BOARD · 201,249 people · 2019
Highest in the ZIP: 18.26 µg/L — OLMITO WSC · 8,952 people · 2019 | 2/2 | SYR4 |
| Dichloroacetic Acid | 8.4 µg/L No EPA limit set Main supplier: BROWNSVILLE PUBLIC UTILITIES BOARD · 201,249 people · 2019
Highest in the ZIP: 16.925 µg/L — OLMITO WSC · 8,952 people · 2019 | 2/2 | SYR4 |
| Dibromoacetic Acid | 10.35 µg/L No EPA limit set Main supplier: BROWNSVILLE PUBLIC UTILITIES BOARD · 201,249 people · 2019
Highest in the ZIP: 13.8 µg/L — OLMITO WSC · 8,952 people · 2019 | 2/2 | SYR4 |
| Gross Beta Particle Activity | 7.44 pCi/L No EPA limit set Main supplier: BROWNSVILLE PUBLIC UTILITIES BOARD · 201,249 people · 2017 | 1/2 | SYR4 |
| Trichloroacetic Acid | 3.8 µg/L No EPA limit set Main supplier: BROWNSVILLE PUBLIC UTILITIES BOARD · 201,249 people · 2019
Highest in the ZIP: 6.17 µg/L — OLMITO WSC · 8,952 people · 2019 | 2/2 | SYR4 |
| Selenium | 5.63 µg/L 11% of the EPA limit 50 µg/L Main supplier: BROWNSVILLE PUBLIC UTILITIES BOARD · 201,249 people · 2019 | 2/2 | SYR4 |
| Monochloroacetic Acid | 3.83 µg/L No EPA limit set Main supplier: BROWNSVILLE PUBLIC UTILITIES BOARD · 201,249 people · 2019 | 2/2 | SYR4 |
| Lead | 3.0525 µg/L 20% of the EPA limit 15 µg/L Main supplier: BROWNSVILLE PUBLIC UTILITIES BOARD · 201,249 people · 2018 | 2/2 | SYR4 |
| Arsenic | 2.85 µg/L 29% of the EPA limit 10 µg/L Main supplier: BROWNSVILLE PUBLIC UTILITIES BOARD · 201,249 people · 2019 | 2/2 | SYR4 |
| Di(2-ethylhexyl) Phthalate | 1.566 µg/L 26% of the EPA limit 6 µg/L Highest in the ZIP: OLMITO WSC · 8,952 people · 2019 | 1/2 | SYR4 |
| Dichloromethane | 1.3 µg/L 26% of the EPA limit 5 µg/L Main supplier: BROWNSVILLE PUBLIC UTILITIES BOARD · 201,249 people · 2019 | 1/2 | SYR4 |
| Xylenes, Total | 1.1 µg/L 0% of the EPA limit 10000 µg/L Highest in the ZIP: OLMITO WSC · 8,952 people · 2019 | 1/2 | SYR4 |
| Atrazine | 0.2000 µg/L 6.7% of the EPA limit 3 µg/L Main supplier: BROWNSVILLE PUBLIC UTILITIES BOARD · 201,249 people · 2019
Highest in the ZIP: 0.2815 µg/L — OLMITO WSC · 8,952 people · 2019 | 2/2 | SYR4 |
| Pfba | 0.0093 µg/L No EPA limit set Main supplier: BROWNSVILLE PUBLIC UTILITIES BOARD · 201,249 people · 2025
Highest in the ZIP: 0.0106 µg/L — OLMITO WSC · 8,952 people · 2025 | 2/2 | UCMR-5 |
| PFOS | 0.0092 µg/L No EPA limit set Main supplier: BROWNSVILLE PUBLIC UTILITIES BOARD · 201,249 people · 2025 | 2/2 | UCMR-5 |
| Pfhxa | 0.0080 µg/L No EPA limit set Main supplier: BROWNSVILLE PUBLIC UTILITIES BOARD · 201,249 people · 2025 | 2/2 | UCMR-5 |
| Pfpea | 0.0076 µg/L No EPA limit set Main supplier: BROWNSVILLE PUBLIC UTILITIES BOARD · 201,249 people · 2025 | 2/2 | UCMR-5 |
| PFOA | 0.0047 µg/L No EPA limit set Main supplier: BROWNSVILLE PUBLIC UTILITIES BOARD · 201,249 people · 2025 | 1/2 | UCMR-5 |
| PFHXS | 0.0044 µg/L No EPA limit set Main supplier: BROWNSVILLE PUBLIC UTILITIES BOARD · 201,249 people · 2025 | 2/2 | UCMR-5 |
| Pfhpa | 0.0041 µg/L No EPA limit set Main supplier: BROWNSVILLE PUBLIC UTILITIES BOARD · 201,249 people · 2025 | 1/2 | UCMR-5 |
| Lead | 0.0 mg/L 0% of the EPA limit 0.0150 mg/L Main supplier: BROWNSVILLE PUBLIC UTILITIES BOARD · 201,249 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 78520
| Supplier | State | Population served |
|---|---|---|
| BROWNSVILLE PUBLIC UTILITIES BOARD | TX | 201,249 |
| OLMITO WSC | TX | 8,952 |
Frequently asked questions about ZIP 78520 tap water
Is the tap water in ZIP 78520 safe to drink?
EPA testing detected 35 contaminants across the water suppliers serving ZIP 78520. 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 78520?
2 public water suppliers report EPA drinking-water monitoring for ZIP 78520. Each is listed above with its population served.
What contaminants are in ZIP 78520's water?
EPA monitoring detected Chlorite, Nitrate, Fluoride, Copper, Barium, and others across this ZIP's suppliers. The full list with levels and sources is above.