Compliance record
PFAS detected
PFAS are industrial “forever chemicals”. These are the EPA's latest
nationwide test results (2023–2025).
| Contaminant | Max | Detection rate | Period |
|---|---|---|---|
| PFOS | 0.0052 µg/L | 2/25 | 2025 |
Other contaminants detected
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 this
system's samples — over 100% is worth reading, but is not by itself a
violation. Where a single sample came in higher than that percentile, it
is noted under the bar. Formal violations are listed separately.
| Contaminant | Level vs EPA limit | Detection rate | Source | Period |
|---|---|---|---|---|
| Nitrate | 7751 µg/L 78% of the EPA limit 10000 µg/L
worst single sample: 11937 µg/L | 2086/2628 | SYR4 | 2012–2019 |
| TTHM | 66.81 µg/L 84% of the EPA limit 80 µg/L
worst single sample: 108.7 µg/L | 720/890 | SYR4 | 2012–2019 |
| Chloroform | 56.809 µg/L No EPA limit set
worst single sample: 95.89 µg/L | 718/894 | SYR4 | 2012–2019 |
| Bromodichloromethane | 9.1 µg/L No EPA limit set
worst single sample: 13.31 µg/L | 702/925 | SYR4 | 2012–2019 |
| Arsenic | 23.8416 µg/L 238% of the EPA limit, at the 95th percentile of samples — 10 µg/L
worst single sample: 28.711 µg/L | 619/883 | SYR4 | 2012–2019 |
| Dichloroacetic Acid | 12.95 µg/L No EPA limit set
worst single sample: 19 µg/L | 242/250 | SYR4 | 2012–2019 |
| Total Haloacetic Acids (HAA5) | 26 µg/L 43% of the EPA limit 60 µg/L
worst single sample: 49 µg/L | 240/250 | SYR4 | 2012–2019 |
| Trichloroacetic Acid | 16.05 µg/L No EPA limit set
worst single sample: 35 µg/L | 240/250 | SYR4 | 2012–2019 |
| Barium | 230 µg/L 12% of the EPA limit 2000 µg/L
worst single sample: 290 µg/L | 109/160 | SYR4 | 2012–2019 |
| Combined Uranium | 5.97073 µg/L 20% of the EPA limit 30 µg/L
worst single sample: 12.9183 µg/L | 109/189 | SYR4 | 2012–2019 |
| Dibromochloromethane | 2.679 µg/L No EPA limit set
worst single sample: 4.1 µg/L | 107/928 | SYR4 | 2012–2019 |
| Lead | 1.21485 µg/L 8.1% of the EPA limit 15 µg/L
worst single sample: 19.036 µg/L | 98/232 | SYR4 | 2012–2019 |
| Tetrachloroethylene | 1.659 µg/L 33% of the EPA limit 5 µg/L
worst single sample: 1.86 µg/L | 92/807 | SYR4 | 2012–2019 |
| Trichloroethylene | 4.62 µg/L 92% of the EPA limit 5 µg/L
worst single sample: 4.84 µg/L | 92/807 | SYR4 | 2012–2019 |
| Copper | 8.1892 µg/L 0.6% of the EPA limit 1300 µg/L
worst single sample: 128.6 µg/L | 83/680 | SYR4 | 2012–2019 |
| Antimony, Total | 0.1350 µg/L 2.3% of the EPA limit 6 µg/L
worst single sample: 0.2010 µg/L | 81/219 | SYR4 | 2012–2019 |
| Selenium | 0.8876 µg/L 1.8% of the EPA limit 50 µg/L
worst single sample: 1.299 µg/L | 73/221 | SYR4 | 2012–2019 |
| Chromium | 8.8498 µg/L 8.8% of the EPA limit 100 µg/L
worst single sample: 21.542 µg/L | 67/203 | SYR4 | 2012–2019 |
| Cadmium | 0.1600 µg/L 3.2% of the EPA limit 5 µg/L
worst single sample: 0.1820 µg/L | 33/225 | SYR4 | 2012–2019 |
| Beryllium, Total | 0.0261 µg/L 0.7% of the EPA limit 4 µg/L
worst single sample: 0.1960 µg/L | 30/198 | SYR4 | 2012–2019 |
| Lead | 0.0 mg/L 0% of the EPA limit 0.0150 mg/L | 29/29 | LCR | 2024 |
| Nitrate-Nitrite | 8270 µg/L 83% of the EPA limit 10000 µg/L
worst single sample: 11000 µg/L | 15/26 | SYR4 | 2015–2019 |
| 1,2-Dichloropropane | 0.6035 µg/L 12% of the EPA limit 5 µg/L
worst single sample: 0.6100 µg/L | 14/807 | SYR4 | 2012–2019 |
| Thallium, Total | 0.0442 µg/L 2.2% of the EPA limit 2 µg/L
worst single sample: 0.0580 µg/L | 13/202 | SYR4 | 2012–2019 |
| Fluoride | 134.5 µg/L 3.4% of the EPA limit 4000 µg/L
worst single sample: 140 µg/L | 12/67 | SYR4 | 2012–2019 |
| Xylenes, Total | 1.3 µg/L 0% of the EPA limit 10000 µg/L | 6/804 | SYR4 | 2012–2019 |
| 1,2-DIBROMO-3-CHLOROPROPANE | 0.0100 µg/L 5% of the EPA limit 0.2000 µg/L | 3/220 | SYR4 | 2012–2018 |
| Bromoform | 0.9900 µg/L No EPA limit set
worst single sample: 1.01 µg/L | 3/926 | SYR4 | 2012–2019 |
| Gross Beta Particle Activity | 5.5315 pCi/L No EPA limit set
worst single sample: 5.7 pCi/L | 2/2 | SYR4 | 2015–2019 |
| Monochloroacetic Acid | 2.575 µg/L No EPA limit set
worst single sample: 2.6 µg/L | 2/250 | SYR4 | 2012–2019 |
| Dibromoacetic Acid | 1.1 µg/L No EPA limit set | 1/250 | SYR4 | 2012–2019 |
| Mercury | 0.0460 µg/L 2.3% of the EPA limit 2 µg/L | 1/69 | SYR4 | 2012–2019 |
79 contaminants tested, none detected
1,1,1-Trichloroethane1,1,2-Trichloroethane1,1-Dichloroethylene1,2,4-Trichlorobenzene1,2-Dichloroethane11Cl-PF3OUdS2,3,7,8-TCDD2,4,5-TP2,4-D4:2 Fts6:2 Fts8:2 Fts9Cl-PF3ONSAdonaAsbestosAtrazineBhc-GammaBenzeneBenzo(A)PyreneChlorobenzeneCyanideCarbofuranCarbon TetrachlorideChlordaneDichloromethaneDalaponDi(2-ethylhexyl) AdipateDi(2-ethylhexyl) PhthalateDinosebDiquatEthylene DibromideEndothallEndrinEthylbenzeneGlyphosateHexachlorobenzeneHfpo-DaHeptachlorHeptachlor EpoxideHexachlorocyclopentadieneLassoMethoxychlorMonobromoacetic AcidNetfosaaNfdhaNmefosaaNitriteOxamylPfbaPFBSPfdaPfdoaPfeesaPfhpaPfhpsPfhxaPFHXSPfmbaPfmpaPFNAPFOAPfpeaPfpesPftaPftrdaPfunaPentachlorophenolPicloramSimazineStyreneTolueneTotal Polychlorinated Biphenyls (PCB)ToxapheneVinyl Chloridecis-1,2-DichloroethyleneLithiumO-DichlorobenzeneP-Dichlorobenzenetrans-1,2-Dichloroethylene
Utility contact
Frequently asked questions about California Water Service - Stockton
Is California Water Service - Stockton tap water safe to drink?
EPA monitoring detected 33 contaminants in California Water Service - Stockton's water. A detection isn't the same as a violation — most levels are within federal limits. See each level and source above, and the utility's annual Consumer Confidence Report for its official compliance status.
What contaminants were detected in California Water Service - Stockton's water?
EPA monitoring detected Nitrate, TTHM, Chloroform, Bromodichloromethane, Arsenic, and others. The full list with the level and data source for each is above.
How many people does California Water Service - Stockton serve?
California Water Service - Stockton reports serving 176,266 people in California, per its EPA record.
Has California Water Service - Stockton had any water quality violations?
The EPA has no formal drinking-water violations on file for California Water Service - Stockton.
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.