What was found in Stockton's water
The highest level seen across the city's suppliers, the EPA limit for each, and where the figure comes from.
| Contaminant | Level vs EPA limit | Suppliers | Source |
|---|---|---|---|
| Nitrate-Nitrite | 1000000 µg/L 10000% of the EPA limit, in the worst sample — 10000 µg/L | 39/48 | SYR4 |
| Nitrate | 11774.6 µg/L 118% of the EPA limit, in the worst sample — 10000 µg/L | 43/48 | SYR4 |
| Copper | 8200 µg/L 631% of the EPA limit, in the worst sample — 1300 µg/L | 25/48 | SYR4 |
| Barium | 400 µg/L 20% of the EPA limit 2000 µg/L | 40/48 | SYR4 |
| Fluoride | 300 µg/L 7.5% of the EPA limit 4000 µg/L | 30/48 | SYR4 |
| Arsenic | 198 µg/L 1980% of the EPA limit, in the worst sample — 10 µg/L | 39/48 | SYR4 |
| TTHM | 157 µg/L 196% of the EPA limit, in the worst sample — 80 µg/L | 10/48 | SYR4 |
| Chloroform | 120 µg/L No EPA limit set | 7/48 | SYR4 |
| Total Haloacetic Acids (HAA5) | 96.3 µg/L 161% of the EPA limit, in the worst sample — 60 µg/L | 10/48 | SYR4 |
| Trichloroacetic Acid | 65.5 µg/L No EPA limit set | 5/48 | SYR4 |
| Dibromochloromethane | 64.9 µg/L No EPA limit set | 10/48 | SYR4 |
| Bromoform | 57 µg/L No EPA limit set | 9/48 | SYR4 |
| Dichloroacetic Acid | 43 µg/L No EPA limit set | 4/48 | SYR4 |
| Bromodichloromethane | 40 µg/L No EPA limit set | 10/48 | SYR4 |
| Bromate | 36 µg/L 360% of the EPA limit, in the worst sample — 10 µg/L | 1/48 | SYR4 |
| Lead | 35 µg/L 233% of the EPA limit, in the worst sample — 15 µg/L | 29/48 | SYR4 |
| Combined Uranium | 34.419 µg/L 115% of the EPA limit, in the worst sample — 30 µg/L | 28/48 | SYR4 |
| Chromium | 28 µg/L 28% of the EPA limit 100 µg/L | 35/48 | SYR4 |
| Dibromoacetic Acid | 22 µg/L No EPA limit set | 10/48 | SYR4 |
| Tetrachloroethylene | 21.9 µg/L 438% of the EPA limit, in the worst sample — 5 µg/L | 5/48 | SYR4 |
| Monochloroacetic Acid | 18.3 µg/L No EPA limit set | 3/48 | SYR4 |
| Selenium | 14 µg/L 28% of the EPA limit 50 µg/L | 23/48 | SYR4 |
| Toluene | 7.1 µg/L 0.7% of the EPA limit 1000 µg/L | 2/48 | SYR4 |
| Monobromoacetic Acid | 3 µg/L No EPA limit set | 6/48 | SYR4 |
| cis-1,2-Dichloroethylene | 2.8 µg/L 4% of the EPA limit 70 µg/L | 1/48 | SYR4 |
| Gross Beta Particle Activity | 2.77 pCi/L No EPA limit set | 2/48 | SYR4 |
| Trichloroethylene | 1.2 µg/L 24% of the EPA limit 5 µg/L | 3/48 | SYR4 |
| Mercury | 0.3200 µg/L 16% of the EPA limit 2 µg/L | 9/48 | SYR4 |
| 1,2-DIBROMO-3-CHLOROPROPANE | 0.2800 µg/L 140% of the EPA limit, in the worst sample — 0.2000 µg/L | 9/48 | SYR4 |
| Ethylene Dibromide | 0.1300 µg/L 260% of the EPA limit, in the worst sample — 0.0500 µg/L | 1/48 | SYR4 |
| PFOS | 0.0135 µg/L No EPA limit set | 2/48 | UCMR-5 |
| Lead | 0.0130 mg/L 87% of the EPA limit 0.0150 mg/L | 47/48 | LCR |
| PFBS | 0.0085 µg/L No EPA limit set | 1/48 | UCMR-5 |
| PFOA | 0.0083 µg/L No EPA limit set | 1/48 | UCMR-5 |
| PFHXS | 0.0047 µg/L No EPA limit set | 1/48 | UCMR-5 |
| Pfhxa | 0.0035 µg/L No EPA limit set | 1/48 | UCMR-5 |
| Pfpea | 0.0033 µg/L No EPA limit set | 1/48 | UCMR-5 |
Water suppliers serving Stockton
Frequently asked questions about Stockton tap water
Is Stockton tap water safe to drink?
EPA testing detected 37 contaminants in the water serving Stockton. 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 Stockton?
48 public water suppliers report drinking-water monitoring for Stockton, California to the EPA. Each is listed above with its population served.
What contaminants are in Stockton's water?
The contaminants EPA monitoring detected in Stockton include Nitrate-Nitrite, Nitrate, Copper, Barium, Fluoride. The full list, with the highest level found 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.