What was found in Nogales'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 | 3280 µg/L 33% of the EPA limit 10000 µg/L Main supplier: NOGALES CITY OF · 22,000 people · 2019
Highest in the city: 6700.5 µg/L — THE GRAND ACRES · 153 people · 2019 | 5/5 | SYR4 |
| Nitrate-Nitrite | 2200 µg/L 22% of the EPA limit 10000 µg/L Main supplier: NOGALES CITY OF · 22,000 people · 2018
Highest in the city: 6360.5 µg/L — THE GRAND ACRES · 153 people · 2017 | 5/5 | SYR4 |
| Fluoride | 2860 µg/L 72% of the EPA limit 4000 µg/L Main supplier: NOGALES CITY OF · 22,000 people · 2018 | 5/5 | SYR4 |
| Copper | 363 µg/L 28% of the EPA limit 1300 µg/L Main supplier: NOGALES CITY OF · 22,000 people · 2018
Highest in the city: 1184 µg/L — THE GRAND ACRES · 153 people · 2019 | 5/5 | SYR4 |
| Barium | 224.3 µg/L 11% of the EPA limit 2000 µg/L Highest in the city: VALLE VERDE WATER COMPANY - EAST · 2,331 people · 2015 | 4/5 | SYR4 |
| Lithium | 57.4 µg/L No EPA limit set Main supplier: NOGALES CITY OF · 22,000 people · 2025 | 1/5 | UCMR-5 |
| TTHM | 18 µg/L 23% of the EPA limit 80 µg/L Main supplier: NOGALES CITY OF · 22,000 people · 2019
Highest in the city: 26.5 µg/L — VALLE VERDE WATER COMPANY - EAST · 2,331 people · 2019 | 5/5 | SYR4 |
| Combined Uranium | 6.86 µg/L 23% of the EPA limit 30 µg/L Main supplier: NOGALES CITY OF · 22,000 people · 2018
Highest in the city: 24.4 µg/L — KINO RANCH 2 · 109 people · 2015 | 3/5 | SYR4 |
| Asbestos | 20.005 MFL 286% of the EPA limit, at the 95th percentile of samples — 7 MFL Main supplier: NOGALES CITY OF · 22,000 people · 2019 | 1/5 | SYR4 |
| Arsenic | 9.935 µg/L 99% of the EPA limit 10 µg/L Main supplier: NOGALES CITY OF · 22,000 people · 2019
Highest in the city: 10.255 µg/L — THE GRAND ACRES · 153 people · 2017 | 5/5 | SYR4 |
| Lead | 3.325 µg/L 22% of the EPA limit 15 µg/L Main supplier: NOGALES CITY OF · 22,000 people · 2018
Highest in the city: 7.262 µg/L — TOWN & COUNTRY - PRESTON · 430 people · 2019 | 5/5 | SYR4 |
| Bromoform | 5.01 µg/L No EPA limit set Highest in the city: VALLE VERDE WATER COMPANY - EAST · 2,331 people · 2019 | 1/5 | SYR4 |
| Total Haloacetic Acids (HAA5) | 3.29 µg/L 5.5% of the EPA limit 60 µg/L Main supplier: NOGALES CITY OF · 22,000 people · 2019
Highest in the city: 3.9 µg/L — VALLE VERDE WATER COMPANY - EAST · 2,331 people · 2019 | 3/5 | SYR4 |
| Gross Alpha, Excl. Radon And U | 3.505 pCi/L 23% of the EPA limit 15 pCi/L Main supplier: NOGALES CITY OF · 22,000 people · 2018 | 2/5 | SYR4 |
| Dibromochloromethane | 3.24 µg/L No EPA limit set Highest in the city: VALLE VERDE WATER COMPANY - EAST · 2,331 people · 2019 | 1/5 | SYR4 |
| Dibromoacetic Acid | 1.955 µg/L No EPA limit set Highest in the city: VALLE VERDE WATER COMPANY - EAST · 2,331 people · 2019 | 1/5 | SYR4 |
| Trichloroethylene | 1.8 µg/L 36% of the EPA limit 5 µg/L Main supplier: NOGALES CITY OF · 22,000 people · 2018 | 1/5 | SYR4 |
| Bromodichloromethane | 1.07 µg/L No EPA limit set Highest in the city: VALLE VERDE WATER COMPANY - EAST · 2,331 people · 2019 | 1/5 | SYR4 |
| Tetrachloroethylene | 0.7185 µg/L 14% of the EPA limit 5 µg/L Highest in the city: VALLE VERDE WATER COMPANY - EAST · 2,331 people · 2019 | 3/5 | SYR4 |
| Lead | 0.0 mg/L 0% of the EPA limit 0.0150 mg/L Main supplier: NOGALES CITY OF · 22,000 people · 2024 | 5/5 | 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 Nogales
| Supplier | Population served |
|---|---|
| NOGALES CITY OF | 22,000 |
| VALLE VERDE WATER COMPANY - EAST | 2,331 |
| TOWN & COUNTRY - PRESTON | 430 |
| THE GRAND ACRES | 153 |
| KINO RANCH 2 | 109 |
Frequently asked questions about Nogales tap water
Is Nogales tap water safe to drink?
EPA testing detected 20 contaminants in the water serving Nogales. 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 Nogales?
5 public water suppliers report drinking-water monitoring for Nogales, Arizona to the EPA. Each is listed above with its population served.
What contaminants are in Nogales's water?
The contaminants EPA monitoring detected in Nogales include Nitrate, Nitrate-Nitrite, 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.