What was found in Montclair'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-Nitrite | 17000 µg/L 170% of the EPA limit, at the 95th percentile of samples — 10000 µg/L Main supplier: MONTE VISTA WD · 56,017 people · 2019 | 1/1 | SYR4 |
| Nitrate | 16000 µg/L 160% of the EPA limit, at the 95th percentile of samples — 10000 µg/L Main supplier: MONTE VISTA WD · 56,017 people · 2019 | 1/1 | SYR4 |
| Fluoride | 290 µg/L 7.2% of the EPA limit 4000 µg/L Main supplier: MONTE VISTA WD · 56,017 people · 2019 | 1/1 | SYR4 |
| Copper | 98 µg/L 7.5% of the EPA limit 1300 µg/L Main supplier: MONTE VISTA WD · 56,017 people · 2019 | 1/1 | SYR4 |
| TTHM | 73.71 µg/L 92% of the EPA limit 80 µg/L Main supplier: MONTE VISTA WD · 56,017 people · 2019 | 1/1 | SYR4 |
| Dibromochloromethane | 27.175 µg/L No EPA limit set Main supplier: MONTE VISTA WD · 56,017 people · 2019 | 1/1 | SYR4 |
| Bromoform | 24.965 µg/L No EPA limit set Main supplier: MONTE VISTA WD · 56,017 people · 2019 | 1/1 | SYR4 |
| Bromodichloromethane | 20.3 µg/L No EPA limit set Main supplier: MONTE VISTA WD · 56,017 people · 2019 | 1/1 | SYR4 |
| Chloroform | 16.48 µg/L No EPA limit set Main supplier: MONTE VISTA WD · 56,017 people · 2019 | 1/1 | SYR4 |
| Total Haloacetic Acids (HAA5) | 14.45 µg/L 24% of the EPA limit 60 µg/L Main supplier: MONTE VISTA WD · 56,017 people · 2019 | 1/1 | SYR4 |
| Chromium | 12 µg/L 12% of the EPA limit 100 µg/L Main supplier: MONTE VISTA WD · 56,017 people · 2019 | 1/1 | SYR4 |
| Dibromoacetic Acid | 9.61 µg/L No EPA limit set Main supplier: MONTE VISTA WD · 56,017 people · 2019 | 1/1 | SYR4 |
| Lead | 8.4 µg/L 56% of the EPA limit 15 µg/L Main supplier: MONTE VISTA WD · 56,017 people · 2019 | 1/1 | SYR4 |
| Arsenic | 5.825 µg/L 58% of the EPA limit 10 µg/L Main supplier: MONTE VISTA WD · 56,017 people · 2019 | 1/1 | SYR4 |
| Dichloroacetic Acid | 4.93 µg/L No EPA limit set Main supplier: MONTE VISTA WD · 56,017 people · 2019 | 1/1 | SYR4 |
| Trichloroacetic Acid | 3.9 µg/L No EPA limit set Main supplier: MONTE VISTA WD · 56,017 people · 2019 | 1/1 | SYR4 |
| Monobromoacetic Acid | 1.225 µg/L No EPA limit set Main supplier: MONTE VISTA WD · 56,017 people · 2019 | 1/1 | SYR4 |
| Tetrachloroethylene | 0.6400 µg/L 13% of the EPA limit 5 µg/L Main supplier: MONTE VISTA WD · 56,017 people · 2019 | 1/1 | SYR4 |
| Trichloroethylene | 0.5800 µg/L 12% of the EPA limit 5 µg/L Main supplier: MONTE VISTA WD · 56,017 people · 2019 | 1/1 | SYR4 |
| 1,1-Dichloroethylene | 0.5200 µg/L 7.4% of the EPA limit 7 µg/L Main supplier: MONTE VISTA WD · 56,017 people · 2019 | 1/1 | SYR4 |
| 1,2-DIBROMO-3-CHLOROPROPANE | 0.2185 µg/L 109% of the EPA limit, at the 95th percentile of samples — 0.2000 µg/L Main supplier: MONTE VISTA WD · 56,017 people · 2019 | 1/1 | SYR4 |
| Pfba | 0.0110 µg/L No EPA limit set Main supplier: MONTE VISTA WD · 56,017 people · 2025 | 1/1 | UCMR-5 |
| PFHXS | 0.0074 µg/L No EPA limit set Main supplier: MONTE VISTA WD · 56,017 people · 2025 | 1/1 | UCMR-5 |
| PFOS | 0.0056 µg/L No EPA limit set Main supplier: MONTE VISTA WD · 56,017 people · 2025 | 1/1 | UCMR-5 |
| Pfpea | 0.0035 µg/L No EPA limit set Main supplier: MONTE VISTA WD · 56,017 people · 2025 | 1/1 | UCMR-5 |
| Pfhxa | 0.0033 µg/L No EPA limit set Main supplier: MONTE VISTA WD · 56,017 people · 2025 | 1/1 | UCMR-5 |
| Lead | 0.0 mg/L 0% of the EPA limit 0.0150 mg/L Main supplier: MONTE VISTA WD · 56,017 people · 2025 | 1/1 | 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 Montclair
| Supplier | Population served |
|---|---|
| MONTE VISTA WD | 56,017 |
Frequently asked questions about Montclair tap water
Is Montclair tap water safe to drink?
EPA testing detected 27 contaminants in the water serving Montclair. 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 Montclair?
1 public water supplier report drinking-water monitoring for Montclair, California to the EPA. Each is listed above with its population served.
What contaminants are in Montclair's water?
The contaminants EPA monitoring detected in Montclair include Nitrate-Nitrite, Nitrate, Fluoride, Copper, TTHM. 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.