What was found in Altadena'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 | 878000 µg/L 8780% of the EPA limit, at the 95th percentile of samples — 10000 µg/L Highest in the city: RUBIO CANON LAND & WATER ASSOCIATION · 9,215 people · 2019 | 2/3 | SYR4 |
| Nitrate | 5700 µg/L 57% of the EPA limit 10000 µg/L Main supplier: LINCOLN AVENUE WATER CO. · 16,088 people · 2019
Highest in the city: 9300 µg/L — LAS FLORES WATER CO. · 4,847 people · 2019 | 3/3 | SYR4 |
| Fluoride | 2780 µg/L 70% of the EPA limit 4000 µg/L Main supplier: LINCOLN AVENUE WATER CO. · 16,088 people · 2019 | 3/3 | SYR4 |
| Copper | 73 µg/L 5.6% of the EPA limit 1300 µg/L Highest in the city: RUBIO CANON LAND & WATER ASSOCIATION · 9,215 people · 2019 | 1/3 | SYR4 |
| TTHM | 66.98 µg/L 84% of the EPA limit 80 µg/L Main supplier: LINCOLN AVENUE WATER CO. · 16,088 people · 2019 | 3/3 | SYR4 |
| Lithium | 53.6 µg/L No EPA limit set Highest in the city: LAS FLORES WATER CO. · 4,847 people · 2024 | 1/3 | UCMR-5 |
| Trichloroacetic Acid | 40.63 µg/L No EPA limit set Main supplier: LINCOLN AVENUE WATER CO. · 16,088 people · 2019 | 3/3 | SYR4 |
| Total Haloacetic Acids (HAA5) | 40.345 µg/L 67% of the EPA limit 60 µg/L Main supplier: LINCOLN AVENUE WATER CO. · 16,088 people · 2019 | 3/3 | SYR4 |
| Chloroform | 39.485 µg/L No EPA limit set Main supplier: LINCOLN AVENUE WATER CO. · 16,088 people · 2019 | 3/3 | SYR4 |
| Combined Uranium | 11.9126 µg/L 40% of the EPA limit 30 µg/L Main supplier: LINCOLN AVENUE WATER CO. · 16,088 people · 2018
Highest in the city: 31.8115 µg/L — RUBIO CANON LAND & WATER ASSOCIATION · 9,215 people · 2019 | 3/3 | SYR4 |
| Dichloroacetic Acid | 19.575 µg/L No EPA limit set Main supplier: LINCOLN AVENUE WATER CO. · 16,088 people · 2019 | 3/3 | SYR4 |
| Bromodichloromethane | 17.9 µg/L No EPA limit set Main supplier: LINCOLN AVENUE WATER CO. · 16,088 people · 2019 | 3/3 | SYR4 |
| Dibromochloromethane | 11.28 µg/L No EPA limit set Main supplier: LINCOLN AVENUE WATER CO. · 16,088 people · 2019 | 3/3 | SYR4 |
| Bromoform | 4.445 µg/L No EPA limit set Main supplier: LINCOLN AVENUE WATER CO. · 16,088 people · 2019
Highest in the city: 4.98 µg/L — LAS FLORES WATER CO. · 4,847 people · 2019 | 3/3 | SYR4 |
| Arsenic | 4.52 µg/L 45% of the EPA limit 10 µg/L Main supplier: LINCOLN AVENUE WATER CO. · 16,088 people · 2019 | 2/3 | SYR4 |
| Dibromoacetic Acid | 3.625 µg/L No EPA limit set Main supplier: LINCOLN AVENUE WATER CO. · 16,088 people · 2019
Highest in the city: 3.88 µg/L — LAS FLORES WATER CO. · 4,847 people · 2019 | 3/3 | SYR4 |
| Tetrachloroethylene | 0.8000 µg/L 16% of the EPA limit 5 µg/L Main supplier: LINCOLN AVENUE WATER CO. · 16,088 people · 2019
Highest in the city: 3.7 µg/L — RUBIO CANON LAND & WATER ASSOCIATION · 9,215 people · 2019 | 3/3 | SYR4 |
| Monochloroacetic Acid | 3.31 µg/L No EPA limit set Main supplier: LINCOLN AVENUE WATER CO. · 16,088 people · 2019 | 1/3 | SYR4 |
| Carbon Tetrachloride | 2.795 µg/L 56% of the EPA limit 5 µg/L Main supplier: LINCOLN AVENUE WATER CO. · 16,088 people · 2019 | 1/3 | SYR4 |
| Trichloroethylene | 2.3 µg/L 46% of the EPA limit 5 µg/L Main supplier: LINCOLN AVENUE WATER CO. · 16,088 people · 2019 | 1/3 | SYR4 |
| PFOS | 0.0190 µg/L No EPA limit set Highest in the city: RUBIO CANON LAND & WATER ASSOCIATION · 9,215 people · 2023 | 1/3 | UCMR-5 |
| PFHXS | 0.0110 µg/L No EPA limit set Highest in the city: RUBIO CANON LAND & WATER ASSOCIATION · 9,215 people · 2023 | 1/3 | UCMR-5 |
| PFOA | 0.0085 µg/L No EPA limit set Highest in the city: RUBIO CANON LAND & WATER ASSOCIATION · 9,215 people · 2023 | 1/3 | UCMR-5 |
| Pfba | 0.0057 µg/L No EPA limit set Highest in the city: RUBIO CANON LAND & WATER ASSOCIATION · 9,215 people · 2023 | 1/3 | UCMR-5 |
| PFBS | 0.0035 µg/L No EPA limit set Highest in the city: RUBIO CANON LAND & WATER ASSOCIATION · 9,215 people · 2023 | 1/3 | UCMR-5 |
| Pfpea | 0.0035 µg/L No EPA limit set Highest in the city: RUBIO CANON LAND & WATER ASSOCIATION · 9,215 people · 2023 | 1/3 | UCMR-5 |
| Pfhxa | 0.0031 µg/L No EPA limit set Highest in the city: RUBIO CANON LAND & WATER ASSOCIATION · 9,215 people · 2023 | 1/3 | UCMR-5 |
| Lead | 0.0 mg/L 0% of the EPA limit 0.0150 mg/L Main supplier: LINCOLN AVENUE WATER CO. · 16,088 people · 2022 | 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.
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 Altadena
| Supplier | Population served |
|---|---|
| LINCOLN AVENUE WATER CO. | 16,088 |
| RUBIO CANON LAND & WATER ASSOCIATION | 9,215 |
| LAS FLORES WATER CO. | 4,847 |
Frequently asked questions about Altadena tap water
Is Altadena tap water safe to drink?
EPA testing detected 28 contaminants in the water serving Altadena. 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 Altadena?
3 public water suppliers report drinking-water monitoring for Altadena, California to the EPA. Each is listed above with its population served.
What contaminants are in Altadena's water?
The contaminants EPA monitoring detected in Altadena 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.