Drinking water quality · 2026
· Verified
What's in City of Stockton, CA tap water
45 contaminants were measured in the City of Stockton, CA water system's 2026 annual report. Each is shown below against its federal limit — 2 sit at or above that limit.
- Reporting year
- 2026
- Contaminants measured
- 45
- Over federal limit
- 2
- Approaching the limit
- 0
- Worst contaminant
- Odor
- Service area
- CA
PFAS — EPA UCMR5 (2023–2025)
1 PFAS compound above EPA limits in City of Stockton, CA
The EPA finalized the first-ever federal drinking-water limits for six PFAS compounds in April 2024. These numbers come straight from EPA's UCMR5 lab dataset — every U.S. system serving more than 3,300 people tested every PFAS sample at an entry point to its distribution system. PFAS not listed below were either tested and not detected, or not yet sampled.
PFOS (Perfluorooctane sulfonic acid)
● Over EPA limit (1.2×)below national p90 (19.900000000000006 ng/L across detecting U.S. systems)
Where your water comes from · EPA SDWIS
City of Stockton, CA's drinking water comes from ground water, drawn from 18 sources.
Source
- WELL NO. · 9
- WELL NO. 03 SSS
- WELL NO. 15 - STANDBY
- DWSP-DELTA WATER SOURCE-RAW
- + 6 more
Treatment
- WELL NO. 15 - TREATED - XCLD - STDBY
- WELL NO. 10R - TREATED - XCLD
- WELL NO. 27 - TREATED - XCLD
- + 14 more
Distribution
Also buys water from STOCKTON EAST WATER DISTRICT.
Historical readings · EPA Six-Year Review (2012–2019)
4 contaminants historically over EPA limits in City of Stockton, CA
Every U.S. public water system reports compliance-monitoring data to EPA. The Six-Year Review releases the 2012–2019 window as a single dataset — here's what your system reported, year by year. Values shown are the highest detection per analyte per year, compared to the federal MCL.
| Contaminant | Worst detection | EPA limit | Years (2012–2019) |
|---|---|---|---|
NITRATE NITRITE worst: 2012 | 500 mg/L 50.0× | 10 mg/L | '12'15'16'17'18 |
BROMATE worst: 2014 | 0.036 mg/L 3.6× | 0.01 mg/L | '12'13'14'15'16'18'19 |
TTHM worst: 2015 | 0.14 mg/L 1.8× | 0.08 mg/L | '12'13'14'15'16'17'18'19 |
HAA5 worst: 2013 | 0.0963 mg/L 1.6× | 0.06 mg/L | '12'13'14'15'16'17'18'19 |
ARSENIC worst: 2013 | 0.009 mg/L 90% near national p90 | 0.01 mg/L | '12'13'14'15'16'17'18'19 |
NITRATE worst: 2012 | 7.01 mg/L within | 10 mg/L | '12'13'14'15'16'17'18'19 |
GROSS BETA worst: 2012 | 1.44 mrem/yr within | 4 mrem/yr | '12 |
BARIUM worst: 2013 | 0.4 mg/L within above national p90 | 2 mg/L | '12'13'14'15'16'17'18'19 |
TCE worst: 2013 | 0.00061 mg/L within | 0.005 mg/L | '13 |
CHROMIUM worst: 2018 | 0.012 mg/L within above national p90 | 0.1 mg/L | '17'18 |
SELENIUM worst: 2013 | 0.0059 mg/L within | 0.05 mg/L | '13 |
DBCP worst: 2017 | 0.00001 mg/L within below national p90 | 0.0002 mg/L | '17 |
FLUORIDE worst: 2016 | 0.2 mg/L within | 4 mg/L | '12'13'16'18 |
URANIUM worst: 2013 | 0.0192 ug/L within near national p90 | 30 ug/L | '12'13'14'15'16'17'19 |
MCAA worst: 2012 | 0.0125 mg/L | — | '12'13'14'15'16'17'18'19 |
TCAA worst: 2012 | 0.0216 mg/L | — | '12'13'14'15'16'17'18'19 |
MBAA worst: 2013 | 0.0014 mg/L | — | '13'14'15'16'17'18'19 |
COPPER worst: 2013 | 0.56 mg/L near national p90 | — | '13'19 |
LEAD worst: 2012 | 0.003 mg/L | — | '12'13'14'19 |
DBAA worst: 2012 | 0.0058 mg/L | — | '12'13'14'15'16'17'18'19 |
DCAA worst: 2012 | 0.022 mg/L | — | '12'13'14'15'16'17'18'19 |
BROMODICHLOROMETHANE worst: 2012 | 0.026 mg/L | — | '12'13'14'15'16'17'18'19 |
BROMOFORM worst: 2012 | 0.0092 mg/L | — | '12'13'14'15'16'17'18'19 |
CHLOROFORM worst: 2012 | 0.099 mg/L | — | '12'13'14'15'16'17'18'19 |
DIBROMOCHLOROMETHANE worst: 2012 | 0.02 mg/L | — | '12'13'14'15'16'17'18'19 |
Physical & aggregate
| Contaminant | Measured | Federal limit | Status |
|---|---|---|---|
| OdorA measure of detectable smell in the water. | 5.8 TONAverageSource water | 3 TONMCL | At or above the limit |
| ColorA measure of visible tint in the water. | 20 UNITSAverageSource water | 15 UNITSMCL | At or above the limit |
| Total Dissolved SolidsTotal dissolved solids — the combined content of all dissolved minerals and salts. | 243.42857142857142 MG/LAverageSource water | 1000 MG/LMCL | Within the limit |
| Specific ConductanceA measure of how well water conducts electricity, which tracks dissolved mineral content. | 201 UMHO/CMAverageEntry point | 1600 UMHO/CMMCL | Within the limit |
| AlkalinityA measure of the water's capacity to neutralize acids. | 36.5 MG/LAverageSource water | None set | Detected — no federal limit |
Inorganic chemicals
| Contaminant | Measured | Federal limit | Status |
|---|---|---|---|
| ChlorideA naturally occurring salt compound. | 23.95 MG/LAverageSource water | 500 MG/LMCL | Within the limit |
| NitriteA compound from fertilizer runoff, sewage, and erosion of natural deposits. | Not detected MG/LHighest single sampleEntry point | 1 MG/LMCL | None detected |
| BromideA naturally occurring salt found in source water. | 0.05975 MG/LAverageSource water | None set | Detected — no federal limit |
Metals
| Contaminant | Measured | Federal limit | Status |
|---|---|---|---|
| Chromium, HexavalentHexavalent chromium ('chromium-6') — the more toxic form of chromium. | 0.136 UG/LAverageSource water | 10 UG/LMCL | Within the limit |
| CalciumA naturally occurring mineral that contributes to water hardness. | Not detected MG/LHighest single sampleEntry point | None set | None detected |
| IronA naturally occurring metal common in groundwater. | Not detected UG/LHighest single sampleEntry point | 300 UG/LMCL | None detected |
| ManganeseA naturally occurring metal from soil and rock. | Not detected UG/LHighest single sampleEntry point | 50 UG/LMCL | None detected |
PFAS ("forever chemicals")
| Contaminant | Measured | Federal limit | Status |
|---|---|---|---|
| 11-Chloroeicosafluoro-3-oxaundecane-1-sulfonic acid (11Cl-PF3OUdS)11-chloroeicosafluoro-3-oxaundecane-1-sulfonic acid, a chlorinated PFAS compound. | Not detected NG/LHighest single sampleSource water | None set | None detected |
| 4,8-Dioxa-3H-perfluorononanoic acid (ADONA)ADONA, a newer-generation PFAS replacement compound. | Not detected NG/LHighest single sampleSource water | None set | None detected |
| 4:2 Fluorotelomer sulfonic acid (4:2 FTS)4:2 fluorotelomer sulfonic acid, a PFAS-related compound. | Not detected NG/LHighest single sampleSource water | None set | None detected |
| 6:2 Fluorotelomer sulfonic acid (6:2 FTS)6:2 fluorotelomer sulfonic acid, a PFAS-related compound. | Not detected NG/LHighest single sampleSource water | None set | None detected |
| 8:2 Fluorotelomer sulfonic acid (8:2 FTS)8:2 fluorotelomer sulfonic acid, a PFAS-related compound. | Not detected NG/LHighest single sampleSource water | None set | None detected |
| 9-Chlorohexadecafluoro-3-oxanonane-1-sulfonic acid (9Cl-PF3ONS)9-chlorohexadecafluoro-3-oxanonane-1-sulfonic acid, a chlorinated PFAS compound. | Not detected NG/LHighest single sampleSource water | None set | None detected |
| Hexafluoropropylene oxide dimer acidHFPO-DA ('GenX chemicals'), a newer-generation PFAS replacement compound. | Not detected NG/LHighest single sampleSource water | None set | None detected |
| Perfluoro-3-methoxypropanoic acid (PFMPA)Perfluoro-3-methoxypropanoic acid, a PFAS-related compound. | Not detected NG/LHighest single sampleSource water | None set | None detected |
| Perfluoro-4-methoxybutanoic acid (PFMBA)Perfluoro-4-methoxybutanoic acid, a PFAS-related compound. | Not detected NG/LHighest single sampleSource water | None set | None detected |
| Perfluoro(2-ethoxyethane)sulfonic acid (PFEESA)Perfluoro(2-ethoxyethane)sulfonic acid, a PFAS-related compound. | Not detected NG/LHighest single sampleSource water | None set | None detected |
| Perfluorodecanoic acid (PFDA)Perfluorodecanoic acid, a longer-chain PFAS 'forever chemical.' | Not detected NG/LHighest single sampleSource water | None set | None detected |
| Perfluorododecanoic acid (PFDoA)Perfluorododecanoic acid, a longer-chain PFAS 'forever chemical.' | Not detected NG/LHighest single sampleSource water | None set | None detected |
| Perfluoroheptanesulfonic acid (PFHpS)Perfluoroheptanesulfonic acid, a PFAS 'forever chemical.' | Not detected NG/LHighest single sampleSource water | None set | None detected |
| Perfluoroheptanoic acidPerfluoroheptanoic acid, a PFAS 'forever chemical.' | Not detected NG/LHighest single sampleSource water | None set | None detected |
| Perfluorohexanoic acidPerfluorohexanoic acid, a shorter-chain PFAS 'forever chemical.' | Not detected NG/LHighest single sampleSource water | None set | None detected |
| Perfluorononanoic acidPerfluorononanoic acid, a PFAS 'forever chemical.' | Not detected NG/LHighest single sampleSource water | None set | None detected |
| Perfluoropentanesulfonic acid (PFPeS)Perfluoropentanesulfonic acid, a PFAS 'forever chemical.' | Not detected NG/LHighest single sampleSource water | None set | None detected |
| Perfluoropentanoic acidPerfluoropentanoic acid, a shorter-chain PFAS 'forever chemical.' | Not detected NG/LHighest single sampleSource water | None set | None detected |
| Perfluoroundecanoic acid (PFUnA)Perfluoroundecanoic acid, a longer-chain PFAS 'forever chemical.' | Not detected NG/LHighest single sampleSource water | None set | None detected |
| PFBAPerfluorobutanoic acid, a shorter-chain PFAS 'forever chemical.' | Not detected NG/LHighest single sampleSource water | None set | None detected |
People also ask about City of Stockton, CA's water
+Is City of Stockton, CA tap water safe to drink in 2026?
The 2026 Consumer Confidence Report for the City of Stockton, CA water utility lists 2 contaminants at or above the federal limit: Odor and Color. Whether that means the water is "unsafe" depends on which contaminant, how long the exposure, and individual health factors. The table on this page shows the measured value, the federal threshold, and the regulated statistic used for compliance.
+What contaminants are in City of Stockton, CA tap water?
45 contaminants were measured in City of Stockton, CA's 2026 Consumer Confidence Report, spanning pfas ("forever chemicals"), disinfection byproducts, and other. 13 have an enforceable federal limit; the rest are detected but unregulated. Every measured value, in the utility's own units, is on this page.
+Which contaminants exceed federal limits in City of Stockton, CA tap water?
2 contaminants in City of Stockton, CA's 2026 report sit at or above the federal limit: Odor (1.9× the limit); Color (1.3× the limit). The EPA enforces these limits against the regulated reporting statistic — typically a running annual average or 90th percentile — not a one-off sample spike.
+What is the worst contaminant in City of Stockton, CA tap water?
The contaminant with the highest measured value relative to its federal limit in the 2026 report is Odor, at 1.9× the federal threshold. It belongs to the physical & aggregate family of contaminants.
+Where does the data on this page come from?
Every value is transcribed from City of Stockton, CA's 2026 Consumer Confidence Report — the annual drinking-water report every U.S. public water utility is required by federal law to publish. The original source document is archived and viewable on this site. A water-quality report covers an entire service area, not a single address.
+How often is City of Stockton, CA's water quality data updated?
Each U.S. public water utility publishes one Consumer Confidence Report per year, covering the prior calendar year's measurements. This page reflects the 2026 report; a new report will replace it once the utility publishes its next annual update.